Panel Study Guide

363. Compiling vs Transpiling?

Transpiling is a special kind of compiling where instead of being converted into machine code it's compiled into another language. Compiling is when source code is converted into machine code.

200. Truncate vs Delete.

Truncate is not transactional because it can't be rolled back. Truncate can modify the object storage attributes so it's not ordinary DML statement. Different dialects might classify it's sublanguage differently Delete removes the contents of a column. Truncate marks the columns for deallocation.

268. What is Type Coercion?

Type coercion is a property of javascript to attempt to compare values of different types because it doesn't have strict types When == is done it will try to change the type of the object for a temporary comparison. A good example is (1 == '1' will be true, even though one is a string and one is a number). This can be avoided by using === which won't try to do any casting.

725. Zuul Filter

Types: Pre - filters execute before routing to the origin Ex: request authentication, choosing origin servers, logging debug info Routing - filters handle routing the request to an origin Post - filters execute after the request has been routed to the origin Ex: adding standard HTTP headers to the response, gathering statistics and metrics, and streaming the response from the origin to the client Error - filters execute when an error occurs during one of the other phases Characteristics Type - defines the stage during the routing flow of WHEN the filter will be applied (can be a custom string too) Execution Order - applied within the Type, defines the order of execution across multiple filters Criteria - the conditions required in order for the filter to be executed Action - the action to be executed if the Criteria is met Filters share a state through a RequestContext which is unique to each request

125. Is there any case the finally block won't execute?

Typically no but there are some extraordinary times where it is possible. If for some reason the exit method is invoked. An error is thrown by the application causing the program to terminate. Power failure.

17. Abstract Class vs Interface

Typically, a programmer would use an abstract class to denote a kind of hierarchy between the abstract class and the classes that extend it. An interface is just implemented, so the interface can be used across a variety of classes that may not be related at all. Can only extend one abstract class Can implement as many interfaces as you would like If a programer wants to have method definitions or contain variables that aren't static and final, they would use an abstract class. The methods in an abstract class can also be overridden, while in an interface, all the methods must be implemented by the class that implements the interface

217. Stored Procedure vs UDF.

UDF = User Defined Functions Functions can only have input parameters and must return a value Procedures can have input and output parameters and don't have to return anything.

336. URL vs URI vs URN

URL (Uniform Resource Locator) - identifies the location of the resource and how to access it URI (Uniform Resource Identifier) - identifies a resource by name, location, or both URN (Uniform Resource Name) - identifies a resource by name in a given namespace but does not specify how to obtain it

251. What is UTF-8?

Unicode Transformation Format 8 means it uses 8 bit blocks to represent a character A character encoding that can contain any unicode characters. 252. What tag would you use to create tables? The table tag Tr is table row Th is table head Td is table data (column data)

630. What is a URI?

Uniform Resource Identifier

208. FULL JOIN vs UNION.

Union combines the results of two or more queries into a single result set that includes the rows that belong to all queries in the union. Full Join - joins everything! Combines the results of both left and right outer joins. The joined table will contain all records from both tables and fill in NULLs for missing matches on either side. Needs at least one match to join.

663. How do you create a SOAP Web Service?

Use JAX-WS Service interface, add @WebService and @SOAPBinding Implement service, add @WebService Main method - publish endpoints (endpoint.publish), give it the url and instance of implementation class Generate WSDL a. Explain all the steps to expose and consume. b. Talk about contract first and contract last. c. Apache CXF for contract last.

648. What is the Web Service Protocol Stack?

Used to define, locate, implement, and make Web services interact with each other (Service) Transport Protocol: responsible for moving messages between network applications (XML) Messaging Protocol: responsible for encoding messages in common XML format (Service) Description Protocol: for describing the public interface to a specific Web service (Service) Discovery Protocol: centralizes services the common registry so that network web services can publish their location and description

695. How to implement Gateway service.

Using the @EnableZuulProxy and the @EnableFeignClient

643. How do I call a resource from Angular?

Using the URL associated with that resource

408. How to inject a template into a view?

Using the ng-template tags, or the router module can also inject template views for entire components. 409. a) (You normally do this with routing, and depending on a route the router will inject the template associated with a specific component).

220. VARCHAR vs VARCHAR2.

VARCHAR - Is reserved in some dialects (Oracle) to support the differentiation between null and empty string. VARCHAR2 - does not distinguish between a null and an empty string.

62. What is varargs?

VarArgs are short for variable arguments, which consist of a number of variable arguments. VarArgs are used when an indeterminate amount of arguments could be included. VarArgs are array-like. They can only be one type and one per method, and they must be used as the last parameter. Javascript equivalent - rest operator, spread operator

67. What is the main purpose of Version Control Software?

Version Control Software is software that is responsible for the management of changes to your files, documents, programs, etc. It records changes so that you can recall specific versions later. An example of a VCS is Git, which we use to store individual and collaborative projects. Git is used for versioning static files, text files, but it can't version binary files.

233. Regular view vs Materialized view.

Views are virtual only and run the query definition each time they are accessed. Materialized views are disk based and are updated periodically based on query definition.

153. What are Views?

Views are virtual tables based on the stored result-set of a SQL statement. A views fields are fields from one or more real tables in the database. You can store views in variables and perform operations to update or alter the view.

343. Another name for web.xml?

Web application deployment descriptor

136. When does a test fail?

When a test assertion evaluates to false (meaning the method didn't execute properly and there is a bug). When the test throws an error or exception. Or if the fail method is invoked resulting in aborting the test as a failure.

114. When is a class fully synchronized?

When the parts of the program that modify the fields of the class are inside a synchronized block. synchronized(MyClass.class) allows only one thread in at a time. synchronized(this) allows one thread per instance.

90. What are Wrapper classes?

Wrapper classes in java are classes bult to add functionality to primitives. Primitives can be turned into a wrapper object that has its own methods that can be used. Integer Has methods to return a base change value as a string Change the current number to a string Calculate the integer value of a number ("1" = 1) Wrappers Byte Short Integer Long Float Double Character Boolean - Also handy for generics since generics don't work on primitive types.

654. XML Schema vs DTD

XML schemas are written in XML while DTD are derived from SGML syntax XML schemas define the datatypes for elements and attributes while DTD doesn't support datatypes XML schemas allow support for namespaces while DTD does not

209. Can I do a subquery in the FROM clause of a SELECT statement? Why?

Yes The result of the subquery in the from clause is a view, that view becomes the table from which the query using the from will select out of as if it were a real database table.

202. Can I do a subquery in an INSERT statement?

Yes insert into prices (group, id, price) select 7, articleId, 1.50 from article where name like 'ABC%'; 203. What is a Cursor? What can I use it for? A cursor is a temporary work area created in the system memory when a SQL statement is executed. A cursor contains information on a select statement and the rows of data accessed by it. This temporary work area is used to store data retrieved from the database, and manipulation of this data.

115. Can an Interface have variables? What are they?

Yes but they are implicitly static and final

406. Is it possible to have module.ts in every component you create?

Yes it is possible but there's not really a reason to do that, best practice is to have one module for you application and then import other modules to that module and inject it into the components and services that need them. Not ideal, you should have one main module and then any custom module, like the routing module or anything that you want to modularize in your application.

265. Is JavaScript case-sensitive?

Yes javascript is case sensitive.

215. Can I do a subquery in an UPDATE statement?

Yes you can. Could go in a WHERE clause. UPDATE Production.Product SET ListPrice = ListPrice * 2 WHERE ProductID IN (SELECT ProductID FROM Purchasing.ProductVendor WHERE BusinessEntityID = 1540);

65. Can constructors be private?

Yes. A private constructor would create a Singleton.

676. Is SOAP stateless?

Yes. No state is saved by client or server in SOAP.

482. How do you configure Hibernate?

You can configure hibernate via a configuration xml, or programmatically. In the xml, you would set up the session factory with the sessionfactory tag. It would contain all the info for your database, like driver, dialect, connection info, and any and all mappings.

416. How do I create a component, what does it receive?

You can create components using the angular cli or create a ts class and decorate it with the @Component decorator. Using the cli will generate the html, css, and spec files for you but those files don't make a component a component and you could create all of those files yourself if you wanted.

483. Why do you need ORM tools like Hibernate?

You need ORM tools like Hibernate because it would take a long time to setup all of the DAOs in a JEE project/environment. Because it abstracts JDBC, it sets up all of your daos after you map your classes. Hibernate can even create the database for you.

616. What is JAX-RS?

a JAVA based programming language API and specification to provide support for created RESTful Web Services.

618. What is JAX-RPC?

a Java application to invoke a Java-based Web service with a known description while still being consistent with its WSDL description

131. Can you test your entire application with JUnit?

(You would have to test all units of it [methods], but we normally separate this testing in different test cases (specific functionality) with multiple tests).

615. SOAP vs REST

*Hard to make a direct comparison since you're comparing a protocol with an architectural style/pattern Main difference is the degree of coupling between the client and server. SOAP clients are heavily coupled to the server, essentially have a rigid contract with each other REST client is more generic, which knows how to use a protocol and standard methods (aka protocol independent) Stack Overflow: SOAP vs REST

176a. What is Domain Integrity?

-Concept of ensuring that the values we store in our database are the appropriate size and type

195. What are the different types of Cursors?

-Static Populates the result set at the time of cursor creation and query results is cached for the lifetime of the cursor. Can move forward and backward. Changes made with UPDATE, INSERT, or DELETE are not reflected in a static cursor -Dynamic Allows you to see updation, deletion, and insertion in the data source while the cursor is open. Hence a dynamic cursor is sensitive to changes to the data source. -Forward only The fastest among all cursors but it doesn't support backward scrolling. You can update, delete data using Forward only cursor. It is sensitive to changes in the original data source. There are different types of forward only cursors. Forward only keyset. Forward only static. Forward only fast forward. -Keyset driven A keyset driven cursor is controlled by a set of unique identifiers as the keys in the keyset. The keyset depends on all the rows that qualified the select statement at the time the cursor was opened. A keyset driven cursor is sensitive to any changes to the data source and supports update and delete operations. They are also scrollable.

593. Spring MVC Workflow.

1. First a HTTP Request is sent 2. The DispatcherServlet receives the request and consults the Handler Mappings to call the appropriate controller 3. The controller takes the request and calls the appropriate service methods based on used GET or POST method 4. The Dispatcher Servlet will get help from the viewResolver to pickup the defined view for the request

352. How many versions of init does HttpServlet have?

2 inits that are inherited from GenericServlet. init() init(ServletConfig config)

637. What are the portType elements?

<operation> inside it are the <input> and <output> tags Types of PortTypes One-Way: The operation can receive a message but will not return a response Request-Response: The operation can recieve a request and will return a response Solicit-Response: The operation can send a request and will wait for a response Notification: The operation can send a message but will not wait for a response

346. How do I declare a Servlet?

<servlet><servlet-name><servlet-class> <servlet-mapping><servlet-name><url-pattern>

636. What are the types of elements in WSDL?

<types> Defines the data types used by the service <message> Defines the data elements for each operation <portType> Describes the operations that can be performed and the messages involved <binding> Defines the protocol and data format for each port type

38. == vs .equals()

== operator - Strict comparison by value and identity; used for both primitive and objects comparison equals() Method - Comparison by value only; method can be overridden ; used for objects comparison

280. == vs ===

== uses type coercion meaning that it will try to see if they hold the same value by casting them to the same type, i.e. "1" = 1

349. Where to forward from, Where to redirect from?

?????????

358. What is extended mapping?

???????????

334. getServletConfig() vs getServletContext()

???????????????

580. Different types of Bean wiring.

@AutoWired on Properties: The annotation can be used directly on properties, therefore eliminating the need for getters and setters @AutoWired on Setters: When the annotation is used on the setter method the setter method is called with the instance of a class when the calling class is created @AutoWired on Constructors: When the annotation is used on a constructor, an instance of the class is injected as an argument to the constructor when the class is created 581. Autowiring. How to configure it? By name: Spring uses the bean name as a default qualifier value By type: Auto-wiring by property data type. If data type of a bean is compatible with the data type of other bean property, auto wire it No (default): Default, no auto wiring, set it manually via "ref" attribute By constructor: byType mode in constructor argument.

586. @Autowired vs @Inject vs @Resource.

@Autowired - Spring property annotation that inject a resource by-type, i.e. by the class or by the interface of the annotated field or constructor. @Inject - Identifies injectable constructors, methods, and fields. This annotation is an almost complete drop-in replacement for Spring's @Autowired annotation. So, instead of using the Spring-specific @Autowired annotation, you might choose to use @Inject. One of the differences between @Autowired and @Inject is that @Inject does not have the required field so in case we fail to find a suitable object to injected it will fail while @Autowired can used required=false and allow null-able field (only if required!). @Resource - Is quite similar to @Autowired and @Inject, but the main difference is the execution paths taken to find out the required bean to inject. @Resource will narrow down the search first by name then by type and finally by Qualifiers (ignored if match is found by name). @Autowired and @Inject will narrow down the search first by type then by qualifier and finally by the name.

698. How do you make Zuul to employ discovery for the routes to services?

@EnableDiscoveryClient - to be used with Discovery to enable dynamic routing

724. Name some annotations for microservice components.

@EnableEurekaServer @EnableEurekaClient @EnableZuulProxy @EnableDiscoveryClient @HystrixCommand @LoadBalance @RibbonClient

692. Annotations of Eureka and what they do.

@EnableEurekaServer - to stand up a registry that other applications can talk to @EnableEurekaClient - to in the list of registered applications

697. Annotations of Zuul and what they do.

@EnableZuulProxy - sets up Zuul so that you can configure routing without Eureka; will turn the Gateway into a reverse proxy that forwards relevant calls to other services

700. Annotations of Hystrix and what they do?

@HystrixCommand(fallbackMethod = "methodName") - place this annotation above a method you want Spring Cloud Netflix Hystrix to look for The annotation wraps that method in a proxy connected to a circuit breaker so that Hystrix can monitor it ONLY WORKS in a class marked with @Component or @Service Example of fallbackMethod is reliable; specify it to provide a placeholder of what you need for users

568. Named queries.

@NamedQuery in the bean Access it quickly Similar to stored procedure

500. What are some common annotations?

@OnetoMany @ManytoOne @ManytoMany @OnetoOne @Entity @Table @Column

388. What is an Injectable?

A Decorator that tells angular that the class is available to the Injector for creation. Objects that are injectable can be created and injected into a component or service.

42. What is a Generic?

A Generic is a template.which enables programmers to specify Generic methods and classes with a single method declarations, a set of related methods, or with a single class declaration An example of a Generic is using the diamond syntax, and an example of using the diamond syntax is when you create a reference to to a List of some object type and initialize an ArrayList.

591. JndiObjectFactoryBean

A JNDI is a Java Name Directory Interface: a Java API for a directory service that allows Java software clients to discover and look up data and resources (in the form of Java objects) via a name A JndiObjectFactoryBean a factory bean that Exposes the object found in JNDI for bean references, e.g. for data access object's "dataSource" property in case of a DataSource

25. BEAN vs POJO

A POJO is a plain old java object A bean is a POJO but with more restrictions Must have a no args constructor Must have private instance variables Must have getters and setters

56. What is a Queue?

A Queue is an interface that implements Collection. It is for data structures that use the first-in-first-out principle, meaning that the first object put into a queue will be the first one to be removed. Queues are also dynamically sized. Implementations of Queue involve the LinkedList, PriorityQueue, and Deque. LinkedLists - is a linear data structure where memory isn't stored in a contiguous location, and each element contains a reference to the next element, which is known as a node. LinkedLists also implement List. PriorityQueue - is a data structure that is ordered according to natural ordering or using a Comparator. A priority queue that uses natural ordering won't allow elements that can't be compared. Deque - (Double Ended Queue pronounced as deck) is a data structure that can be accessed from both ends, meaning that it can be used as a FIFO or LIFO data structure

60. What is Singleton?

A Singleton is a class that can only have one instance of that class at a time. Its purpose is to limit the number of objects to only one. An example of a Singleton would be a Factory. After the first time, if we try to create another instance, it will point to the first instance created. To design a Singleton class, you make the constructor private and write a static accessor method that gets your Singleton.

304. App Server vs Web Server

A Web server exclusively handles HTTP requests, whereas an application server serves business logic to application programs through any number of protocols. Web server is responsible for serving static content over HTTP while Application server is responsible for serving dynamic content, managing EJB, lookup over JNDI, and application security.

367. What is a Webpack?

A Webpack is a module bundler. Takes care of bundling your application for deployment alongside a separate task runner.

43. What is a Wrapper Class?

A Wrapper Class is meant to encapsulate primitive data types to turn them into objects using an operation of the JVM called autoboxing. You can also unbox an object to a primitive. Can use object methods Can be used with Generics

296. What is a Callback Function?

A callback function is a function placed into a parameter of another function to make sure that certain steps are done when that function ends.

78. Is a catch block needed?

A catch block is needed if you have a checked exception otherwise the JVM won't compile the code, but if you throw the exception in the method signature, you can also simply have a try-finally block.

275. What are Closures?

A closure is an inner function that has access to the outer functions variables. A closure has three scope chains: its own scope, outer functions, and globals.

386. What is an Observable?

A collection that arrives over time. Often used to handle async data requests.

176. What is Referential Integrity?

A concept that states that when data references another source of data, that that data exists. In SQL data sources are tables, and foreign keys are the external references. In SQL you can't delete a value from a table if it's referenced from other tables, this would cause the loss of referential integrity otherwise. Cascading is the ripple effect of changing a parent key on any child keys referencing it this is present in both Referential and Domain Integrity

157. What is a Cursor?

A cursor is a temporary work area created in the system memory when a SQL statement is executed. A cursor contains information on a select statement and the rows accessed by it. This temporary work area is used to store the data retrieved from the database, and manipulate this data. Different from view because cursors are defined and used within the scope of a stored procedure.

45. What is an Array?

A data structure containing like-typed variables that is initialized with a certain block of memory that use indexes which allow for consistent random access

355. Front Controller.

A design pattern for full-stack applications. Front-end sends a request to the back-end. Back-end has a single servlet that is the request dispatcher it receives all requests. When the dispatcher gets a request it consults the handler mapper which tells it by the request type url and other aspects what controller to send the request to. The dispatcher sends it to the appropriate controller who uses a service to call a DAO. The DAO sends a query to the database and receives the databases response which it sends back through the service. The service returns it to the controller who passes it to the dispatcher. If the request was for a page then the servlet would communicate with the view resolver to produce the correct view on the front-end. The dispatcher writes a response with the data in it to the response stream to the front-end producing the view or passing the data for manipulation or display.

575. What is an automatic dirty checking?

A feature that updates the db when we modify the state of an object in a transaction Saves us effort for asking hibernate to update the database after a modification

201. DATE vs TIMESTAMP.

A few main differences Timestamp converts from current time to UTC and back, while Datetime doesn't do any time conversion Timestamp differs by time zone while datetime will remain constant. Timestamp can also be indexed while datetime cannot. Queries with datetime cannot be cached while queries with timestamp will be cached.

357. What are filters?

A filter in the context of java servlets is an object that performs filtering tasks on either the request to a resource or on the response from a resource. It's used to limit input and output from a resource to only requests and responses fitting a set of rules defined by the filter.

163. What is a Foreign Key?

A foreign key is a column (or columns) that references a column that is the primary key of another table. The purpose of the foreign key is to insure referential integrity of the data.

247. What is Bootstrap?

A front-end, open source toolkit used to speed up development with HTML, CSS, and JavaScript. Built for mobile first web-development Using a grid system.

26. What is a hashcode?

A hashcode is an identifier for an object that has been converted to an integer. Although a hashcode should be unique, hash collisions may happen. A hash collision is when two different objects share a hashcode. Two same objects will have the same hashcode, but two same hashcode won't necessarily refer to the same object.

228. What is a natural join?

A join operation that creates an implicit join clause for you based on the common columns in the two tables being joined. Common columns are columns that have the same name in both tables. Can be an inner join, left outer join, or a right outer join.

128. What is a Factory?

A large class that's used to instantiate objects from a particular class Typically a singleton because of its complexity Used to instantiate classes with numerous and complex constructors.

54. What is a LinkedList?

A linear data structure. Not contiguous location. Nodes are used to link elements by storing a reference to the next linked element.

285. What is a Listener?

A listener is an object that waits for events or actions to occur In javascript the most used is the Event Listener, when an event occurs the element with an event listener attached will call or execute some type of function to make the web page more interactive.

425. Publisher/Subscriber.

A messaging pattern where senders of messages (publishers) categorize published messages into classes without knowing how many subscribers there may be or which one's are using their data. Subscribers express interest in one or more classes and only grab messages that are of interest without knowing how many or which publisher they're getting data from.

12. What is a Constructor?

A method that creates an instance of a class based on the parameters passed into the constructor

469. What is Autoscaling?

A method used in cloud computing where the number of instances for a server scales automatically based on the connection and request load.

117. What are default methods in an interface?

A method which is declared as default in an interface can have an implementation in the interface.

382. What is a Pipe?

A pipe takes in data as input, does some transformations, returns some output Used for writing formatting tasks or other repetitive tasks. That way you only have two write it once and then import it and make a call to it wherever you need it.

161. What is a Primary Key?

A primary key is a field in a table which uniquely identifies each row/record in a database table. Primary key columns cannot be null. A table can only have one primary key, which may consist of single or multiple fields.

58. What is a Process?

A program in execution is often referred to as a process. A process can consist of multiple threads, and a thread is the smallest part of the process that can execute concurrently with other threads of the process.

387. What is a Provider?

A provider is an object or class that provides a component with data. In short terms it is a service that is registered to a component or module. Providers is a field or attribute in component or module decorators that tell angular what services to inject into the component.

183. What is a Scalar Function?

A scalar function is a function that takes data and modifies it, it doesn't do any calculations with it, just altering the look or returning metadata of the query. Good examples are: Upper case Lower case Mid Len Round Now format

155. What is a Schema?

A schema is a collection of database objects associated with one particular database username. The username is called the schema owner, or the owner of the related group of objects. You can have multiple schemas in a database. Schema types Snowflake - normalized; different relationships between tables Star - not normalized; all tables point back to one fact table

273. What is a self-invoking function?

A self-invoking function is started automatically without being called, this is done right after it's created. This is used for avoiding naming conflict as well as for achieving encapsulation. Variables or declared objects are not accessible outside this function.

222. What is a SELF JOIN?

A self-join is a query in which a table is joined (compared) to itself. Self joins are used to compare values in a column with other values in the same column in the same table. A practical use for self joins is obtaining running counts and running totals in a SQL query.

158. What is a Sequence?

A sequence is a user-defined, schema-bound object that generates a sequence of numeric values according to the specification with which the sequence was created. The sequence of numeric values is generated in an ascending order or descending order at a defined interval and can be configured to restart when exhausted. You can use a sequence to define a row by a unique value.

366. What does it mean to be a Single Page Application

A single page application (SPA) is a web application or web site that interacts with the user dynamically by rewriting the current page rather than loading a whole new page from a server. Interaction with the single page application often involves dynamic communication with the web server behind the scenes.

102. What is a Singleton?

A singleton is an object that is very large or very complex. Because of this it is inefficient to have multiple instances of these objects in an application So to solve this you create one instance and pass it around your application to the methods that need it.

27. STACK vs HEAP

A stack refers to Java Stack Memory, which is LIFO. It's a stack of memory. Whenever a method is invoked, a new block is created in the stack memory for the method to hold local primitive values and reference to other objects in the method. As soon as method ends, the block becomes unused and become available for next method. Stack memory size is much less compared to Heap memory. StackOverflow A heap refers to the Java Heap Space, which is used by Java runtime to allocate memory to Objects and JRE classes. Whenever we create any object, it's always created in the Heap space. Garbage Collection runs on the heap memory to free the memory used by objects that don't hold any more reference. Any object created in the heap space has global access and can be referenced from anywhere of the application. OutOfMemoryError

173. What is a Dirty Read?

A transaction anomaly that occurs when a transaction is allowed to read data from a row that has been modified by another running transaction that has not been committed yet.

174. What is a Non-Repeatable Read?

A transaction anomaly that occurs when data is read twice in the same transaction and returns different values because another transaction has modified the data between the reads. (more about update problems)

181. What is Transitive Dependency?

A transitive dependency in a database is an indirect relationship between values in the same table where one value is determined by another value.

154. What are Triggers? When can it execute?

A trigger is a database object/block of code that executes one or more SQL statements when a specified operation/event is executed. You can define when a trigger fires when you define the trigger Events are any DML (Delete, Update, Insert) Can specify a chronological relationship to these events (whether they occur before or after their execution)

31. What is a Try-Catch-Finally Block?

A try-catch-finally block is used to handle checked exceptions so that the JVM will compile the code. In the try block, the programmer enters the code that may need to be caught. In the catch block, the programmer handles the potential exception or exceptions. The finally block will execute after the catch block always, unless the system exit method is called or the power fails or any such other exceptional states.

446. What is GREP?

A unix/linux command that searches files for the occurence of a string that matches a specific pattern.

24. How do you achieve Encapsulation?

Access modifiers

572. Spring is loosely coupled. Explain why we say this.

Achieved by means of a design that promotes single-responsibility and separation of concerns. A loosely-coupled class can be consumed and tested independently of other (concrete) classes

600. How to configure AOP?@Aspect at the class

Advice annotations - include path of execution

186. What is a Subquery?

Also called an inner or nested query A query within another SQL query and embedded within the WHERE clause. Used to return data that will be used in the main query as a condition to further restrict the data to be retrieved.

205. ALTER vs UPDATE.

Alter is a table scope command (DDL) Update is row scoped (DML) Alter table is altering the number or attributes of the columns and the functions in the table. Update is altering the data in the rows of the table.

466. What is AMI?

Amazon Machine Image - an OS image to run on an EC2, that is the operating system that the ec2 has There are a few to choose from including amazon linux, ubuntu, windows, etc.

476. What is Route 53?

Amazon route 53 is a scalable and highly available DNS There you can register domain names for you applications Route internet traffic to your domain And check on the health of your application.

471. What is S3?

Amazon's Simple Storage Service. Designed with a simple web service interface that can be used to store and retrieve data. Can also be used for static web hosting.

250. What is ANSI?

American National Standards Institute. Creates standards for the computer industry. Sets standards throughout a wide range of technical areas from electrical specifications to communication protocols.

141. What is an ERD?

An ERD is a Entity Relationship Diagram, which is a diagram that maps out your database tables and the multiplicity and their relationships to each other. Creating an ERD during your design phase helps you visualize what you need to code when setting up the architecture of your database.

74. Why would you use an Abstract class over an Interface?

An abstract class, unlike an interface, doesn't work like a contract, so all of the inherited methods don't have to be implemented, and those that you want to use can be used using the parent's definition or by overriding. Abstract classes also allow you to inherit class variables, as long as they aren't static. Abstract classes are used when the relationship between the abstract class and the class extending it is hierarchical, when you want to inherit states, and when you want to define a method definition. (Interfaces can actually also provide default methods without affecting implementing classes, as it includes an implementation. An implementing class can override the default implementation provided by the interface.)

613. What is REST?

An architecture Constraints defining a restful system Client server architecture Stateless Cacheability Layered system - a client can't tell if it's connected directly to the RESTful service or an intermediary Code on demand - Servers can temporarily extend or customize the functionality of a client by transferring executable code Uniform interface

297. What is the AJAX workflow?

An event in our browser occurs and a new XML/HTTPRequest is created The request is opened and sent Receives our request and processes it Create a response and return it to our client Browser processes response and updates the webpage

50. What is a TreeSet?

An implementation for the SortedSet interface No duplicate values Doesn't preserve the insertion order of elements but elements are sorted by keys An implementation of a self-balancing binary search tree

156. What is an Index?

An index is used to speed up the performance of queries. It does so by reducing the number of database data pages that have to be scanned/visited. In SQL Server, a clustered index determines the physical order of data in a table. There can only be one clustered index per table (the clustered index is the table).

72. What is an Interface?

An interface is a class that other classes can implement. It is a contract which includes method signatures (but no method definitions) and sometimes static final variables which must all be implemented by classes that use that interface. An interface is helpful for providing semantic meaning across a number of classes without implying them to be related via inheritance extension.

51. What is a List?

An interface that implements Collection An ordered collection of objects in which duplicate values can be stored By ordered, it means that it preserves the insertion order to allow positional access and insertion of elements

46. What is a Set?

An interface which extends collections. A set is an unordered collection of objects which can only contain unique values. Set has various methods to add, remove, size and more to enhance the usage of this interface

6. Class vs Object

An object is an instantiation of a class The class is the blueprint that provides the states and behaviors its instantiated objects will have

424. What is Observable?

An observable is a way of handling async calls for data. Observables are lazy collections of multiple values that populate over time. In angular Observables are a class of generic type that you can return from an asynchronous call to make sure the data is there when you need it. You can subscribe to the call and when the observable populates you can get the data you need from it Observables are often prefered over promises because they can handle multiple events whereas promises are for a single event. Observables are also cancellable where a promise is not

365. AngularJS vs Angular4

Angular JS is 1.0-1.6, Angular is 2+ Both use dependency injection Angular JS is in JavaScript Angular is in TypeScript Decorators are unique to Angular2

364. What is Angular?

Angular is a framework built on top of typescript using declarative templates, dependency injection, end to end tooling, and integrated best practices to speed up the development process. Angular defines components and uses dependency injection to carry out DOM manipulation for you.

571. How do you create a bean in Hibernate?

Annotations @Entity @Table (name="") @Column @Id @GeneratedValue (specify strategy) @JoinColumn Specify multiplicity @OneToMany, @ManyToOne, @ManyToMany @MappedBy XML

468. What are the types of ELB?

Application load balancers Network load balancers Classic load balancers

488. What are Application Transactions?

Application transactions are any action that needs to modify data stored in the database. There are different ways of ensure ACID properties of these transactions.

126. Array vs ArrayList

ArrayList - dynamically sized, takes objects, Collection

63. ArrayList vs Vector?

ArrayList and Vectors can both be dynamically sized, but a Vector increases by double its size while an ArrayList increases by half of its size. Both Vectors and ArrayLists implement List, and they both allow RandomAccess. A Vector, however, is thread safe and ArrayLists are not. Meaning a change in a vector used across different threads would be reflected in the instance of that vector across those threads.

99. LinkedList vs ArrayList

ArrayList internally uses an array to store data. LinkedList uses doubly linked lists to store data. ArrayList is slower with manipulation because it might require bit-shifts in memory (if an object is deleted for example). LinkedList is faster for manipulation because it uses doubly linked lists to store data. ArrayList can act only as a list because it only implements the list interface alone. LinkedList can act as both a list and a queue because it implements both List and Deque. ArrayList is better for storing and accessing data. LinkedList is better for manipulating data.

599. What is AOP?

Aspect Oriented Programming Code injection Address cross-cutting concerns Transactions Authorization Logging Aspect, Advice, JoinPoint, Pointcut

449. How do you configure Jenkins?

Assuming jenkins is already installed: Run Jenkins as a service Create Users - this is for added security and role management, not anyone can deploy or rollback builds, not everyone can see build results, etc. Create a Jenkins project - this is the actual project configuration of jenkins (assuming you have necessary plugins) Click new item Select the project type: Freestyle project Maven project External Job multi-configuration project Set up the source repository for this you can generate a github hook that jenkins can use on github. Next you can add build steps that jenkins should take when activated. After that save your changes and whenever that hook is activated jenkins will pull the repo and execute the specified build steps.

448. How do you connect to EC2 from Putty?

Assuming your ec2 is up and running and you have putty installed properly and open: Download your ec2 key pair file from the aws website Convert the pem file to ppk file using puttygen make sure to save it somewhere safe. Open up putty Enter the ec2 hostname usually in the format of user_name@public_dns_name. (changes based on AMI type) Open the auth page/tab and select your ppk for authentication Once that's done click open to start the SSH session.

168. What is Atomicity?

Atomicity - each transaction is all or nothing, if any part of the transaction fails the whole thing fails, and then the database is rolled back to its last consistent state.

375. What is a Attribute Directive?

Attribute Directives change the appearance or behavior of a DOM element, component, or another directive. Attribute directives are used as attributes of elements Must be annotated with the @Directive decorator A good example is the NgStyle directive which is built-in to angular.

584. Stereotype Annotations.

Below are class-level @Component: Such classes are considered as candidates for auto-detection when using annotation-based configuration and classpath scanning @Controller: allowing for implementation classes to be autodetected through classpath scanning. It is typically used in combination with annotated handler methods based on the RequestMapping annotation @Service: "an operation offered as an interface that stands alone in the model, with no encapsulated state @Repository: a mechanism for encapsulating storage, retrieval, and search behavior which emulates a collection of objects exception handler included, so don't need to write try-catch block. (because of automatic translation feature)

384. What is a Binding?

Binding the function is a way of setting a function context. .bind() when you want that function to later be called with a certain context, useful in events. Use .call() or .apply() when you want to invoke the function immediately, and modify the context. Call/apply call the function immediately, whereas bind returns a function that when later executed will have the correct context set for calling the original function. This way you can maintain context in async callbacks, and events. The first argument in the bind method is the method that will be bound to this. Data-binding One-way and two-way binding When the state of a field changes on the web page the value of the variable in the script is updated as well.

68. What are the data types in Java? (8)

Boolean - true or false Default false 1 bit Char - character type whose values are 16-bit Unicode characters Default \u0000 16 bits Byte Default 0 8 bits Short Default 0 16 bits Int Default 0 32 bits Long Default 0 64 bits Float Default 0.0 32 bits Double Default 0.0 64 bits

399. What is bootstrapping?

Bootstrapping is the creation of specified components when the app is loaded and the addition of those components to the browser DOM. Components to be bootstrapped are specified by listing them in the NgModule's bootstrap array.

64. TreeSet vs HashSet?

Both TreeSets and HashSets implement the Set interface. TreeSets also implement the SortedSet interface. The TreeSet is an implementation of a binary self-balancing tree, whereas HashSets are sets but with their values hashed.

644. Complex Types vs Simple Types

Both are W3C Schema Types Simple Types cannot have element children or attributes Complex Types can have element children or attributes

518. Merge vs Update

Both are updating information that exists in the database Merge - can be called on objects that are persisted Update - can only be called on objects that are transient SaveOrUpdate - calls either save or update based on if the identifier exists Save - store the object into the database; persists transient instance and returns id of the entity created

567. Dynamic insert vs update.

Both tell Hibernate whether to include data in statements Dynamic insert ask whether null properties should be included in INSERT statements Dynamic update ask whether updated or modified data should be included in UPDATE statements

703. Workflow of a Docker? How does an image reach the container?

Build Application Build Image Deploy Application Test Application

629. What is Uniform-Interface?

By applying the software engineering principle of generality to the component interface, the overall system architecture is simplified and the visibility of interactions is improved

394. What is CLI?

CLI stands for Command Line Interface. Set of commands that you can run on the command line The Angular CLI is used for constructing the scaffolds of apps and components from the command line.

628. What does it mean to be Cacheable?

Cache constraints require that the data within a response to a request be implicitly or explicitly labeled as cacheable or non-cacheable. If a response is cacheable, then a client cache is given the right to reuse that response data for later, equivalent requests.

553. L1 vs L2.

Caching - won't have to hit database each time L1 caching - session only L2 caching - session factory basis; information you would want to access throughout sessions Expensive operation to store; lots of memory to store Query caching - query resultset

282. What is Capturing?

Capturing is another form of event propagation. Capturing works the opposite of bubbling: When an event is fired and parent and children elements have handlers registered the parent's handler fires first and then the event trickles down to the child.

242. What is CSS?

Cascading style sheet Defines how the elements on the page will look.

231. Clustered vs Unclustered index.

Clustered indexes sort and store the data rows in the table or view based on their key values. Nonclustered indexes have a structure separate from the data rows which contains the nonclustered index key values and each key value has a pointer to the data row.

66. What is the difference between 'Collection' vs 'Collections'

Collection is the interface that implements Iterable. It marks a class as a Collection and therefore also Iterable. Collections is the java util package that provides static methods available to Collection classes.

609. Load time vs Compile time Weaving.

Compile-time weaving is the simplest approach. When you have the source code for an application, ajc will compile from source and produce woven class files as output. The invocation of the weaver is integral to the ajc compilation process. The aspects themselves may be in source or binary form. If the aspects are required for the affected classes to compile, then you must weave at compile-time. Aspects are required, e.g., when they add members to a class and other classes being compiled reference the added members. Load-time weaving (LTW) is simply binary weaving defered until the point that a class loader loads a class file and defines the class to the JVM. To support this, one or more "weaving class loaders", either provided explicitly by the run-time environment or enabled through a "weaving agent" are required.

159. What is a Constraint? Give a few examples.

Constraints are rules used to limit the type of data that can go into a table. Used to maintain the accuracy and integrity of the data inside the table. Can be divided into two types, column level and table level. Column level constraints limit only column data Table level constraints limit the whole table. Most used constraints include: NOT NULL UNIQUE PRIMARY KEY FOREIGN KEY CHECK DEFAULT

354. How to maintain user state?

Cookies initialized when the user logs in. Send the session id from the cookie in HTTP requests. Access the HttpSession object from the request object using the getSession() method.

212. CREATE vs INSERT.

Create is a DDL command that is used to make a table, procedures, and functions. INSERT is a DML command that is used to add a row to a table.

489. What are the query types in Hibernate?

Criteria API Native SQL HQL

310. What is DTD?

DTD stands for Document Type Definition. This defines the elements that may be included in the document, what attributes the elements have, and the ordering and nesting of the elements. Documents validated against DTD is considered to be "Well-Formed" and "Valid"

420. What is Data Binding?

Data binding is essentially creating a connection between the application UI and the business logic. When a front end reference changes the state of the bound object or variable the variable itself updates with the changes 421. Which are the types of Data Binding? Interpolation - property name is enclosed in double curly braces {{ propertyName }}. Property Used to bind values of component/model properties to the HTML element might change the behavior of the element depending on values [property]="expression". Attribute set the values of an attribute directly, must only be used when the element doesn't have the property itself. Done in a way similar to property binding but using an attribute prefix [ attr.attr-name ] = 'expression' Class add and remove CSS class names from HTML elements Similar to attribute binding but starts with the class prefix not the attribute prefix [class.Class-Name]='expression' Style Used to set inline styles to the HTML element Style itself adds only a single line to the inline style To add multiple styles with angular you can use the NgStyle directive.

175. What is a Phantom Read?

Data getting changed in a transaction by other transactions in which rows are added or removed resulting in different result sets. (more about insert/delete problems)

85. What is a deadlock?

Deadlock is another component of the producer consumer problem. Deadlock is when two or more threads are waiting for resources that the other(s) have.

371. What are decorators?

Decorators are a core concept of Angular 2+. The whole purpose of the decorator is to store metadata about a class, method, or property. The component decorator tells angular that a component is a component and then it knows what it needs to do with it. It's more of an identifier than anything which sounds simple but it's very important so that angular can differentiate components and their purposes.

13. What are the types of Constructors?

Default (created by the JVM for you if no constructor is specified) No args Other

362. What does the Arrow Function (=>) do?

Defines a lambda function. Don't need to type "function" Lexically captures the meaning of this. Lexically captures the meaning of arguments.

678. WSDL Tags in detail.

Definition − It is the root element of all WSDL documents. It defines the name of the web service, declares multiple namespaces used throughout the remainder of the document, and contains all the service elements described here. Types − The data types to be used in the messages are in the form of XML schemas. Message − It is an abstract definition of the data, in the form of a message presented either as an entire document or as arguments to be mapped to a method invocation. Port type − It is an abstract set of operations mapped to one or more end-points, defining the collection of operations for a binding; the collection of operations, as it is abstract, can be mapped to multiple transports through various bindings. Operation − It is the abstract definition of the operation for a message, such as naming a method, message queue, or business process, that will accept and process the message. Binding − It is the concrete protocol and data formats for the operations and messages defined for a particular port type. Service − It is a collection of related end-points encompassing the service definitions in the file; the services map the binding to the port and include any extensibility definitions.

377. What is a Dependency Injection?

Dependency Injection is a form of Inversion of Control, where you give up control to an outside entity. The outside entity provides you the instance of the dependency that you need, so that you don't worry about the implementation of your resource, but instead focus on the business logic you are constructing. Dependency Injection is beneficial because it keeps your classes loosely coupled and isolates test cases.

139. How do you test your application automatically?

Depends what environment you're developing your application in, If you're using an IDE a lot of them have settings to run tests automatically, either when you run the application or after it completes a build process. Certain processes and applications can use hooks to run tests when a commit or push is made as well (Jenkins, husky).

104. Where are variable references stored?

Depends what type of variables they are, and their scope, local variables or variables with block scope are stored in the stack. Objects and their instance variables are stored in the heap.

311. What is an XML Schema?

Describe the structure of an XML document Provides a more powerful alternative to DTD

690. Any disadvantage in using microservices.

DevOps complexity - Due to several moving parts of the application. It becomes complex. Increased Resource use - Initial investment to run these applications are high because all the independently running components need their own containers Ease overhead - people need to communicate to make sure update doesn't occur error on other services, Cost to monitor each individual service Databases are more difficult to keep normalized

432. What is DevOps?

DevOps is the practice of operations and developers participating together throughout the service lifecycle. From design to deployment to production support.

433. Why would you need DevOps?

Devops describes a culture and a set of processes that bring development and operations teams together to complete software development. Once practices are in place development is extremely fast compared to other development processes, allowing multiple iterations. This allows you to build the base product and ad multiple features and fixes in quick succession. DevOps pipelines work in a cycle allowing for continuous development, integration, and deployment. Netflix and spotify have extremely effective build pipelines.

454. What is the U-Model Methodology?

Didn't discuss this

455. What is the College Model Methodology?

Didn't discuss this

464. What is EC2?

Elastic Compute Cloud Essentially a virtual machine on a server with a specific allocation for hardware resources based on plans The more resources the more expensive Used for running a server to host an application that users can connect to.

467. What is ELB?

Elastic Load Balancing A load balancing service for AWS. ELB automatically distributes incoming application traffic and scales resources to meet traffic demands.

307. What are the rules for an element in XML?

Element names are case-sensitive Element names must start with a letter or underscore Element names cannot start with the letters xml (or XML, or Xml, etc) Element names can contain letters, digits, hyphens, underscores, and periods Element names cannot contain spaces

257. What do elements and attributes need to be to achieve XHTML?

Elements XHTML elements must be properly nested XHTML elements must always be closed XHTML elements must be in lowercase XHTML documents must have one root element Attributes Attribute names must be in lower case Attribute values must be quoted Attribute minimization is forbidden

308. Element vs Attribute

Elements can be viewed as containers that stores text, elements, etc... Attributes defines the property of an element

36. What are some types of exceptions?

Errors: StackOverflow, VirtualMachineError, OutOfMemoryError Exceptions: FileNotFoundException, IOException, SQLException RuntimeException: ArrayIndexOutOfBounds, NullPointerException, RuntimeException

458. What is SonarQube?

Essentially a linting tool Used to encourage best practices, helps with things like format and identifying potential bugs.

412. What is a Decorator?

Essentially decorators are to angular as annotations are to java They're identifiers with metadata that tells angular what to do with a component or class.

281. What is Bubbling?

Event bubbling is a form of event propagation. Event bubbling propagates events from children to parents. An event gets fired and is handled by a child element, from there it propagates up to parents with handlers for the event.

398. What are Event Emitters?

EventEmitter is a class in angular that's used by directives and components to emit custom events. Event emitters are defined as output events which is where you can create them and you can reference those events in the component and specify what they emit.

266. What is Prototypical Inheritance?

Everything in javascript is an object Each object has a private property which holds a link to another object called its prototype. When you construct an object the prototype chain links all the way up to Object the parent of everything in javascript to build the object.

415. What is a Component?

Everything! Everything in angular is a component. Components are simply typescript classes that are decorated with the @Component decorator which allows you to add more metadata.

30. What is an Exception? What class does it extend?

Exception extends Throwable, which has Exception and Errors as subclasses and RuntimeException, which is a subclass of Exception.. Exceptions are events in execution which deviate or interrupt from the normal flow of execution. You can throw and catch exceptions.

101. Different between Exception and Error?

Exceptions and errors are both catchable but unlike exceptions catching an error can't save your application. Errors are references to larger issues that require termination of the application, there is nothing you can do to keep your application running once an error is thrown while exceptions can be caught and handled to keep your application running.

107. What is the difference between an Exception and a RuntimeException?

Exceptions are the super class of runtime exceptions. Exceptions that aren't runtime exceptions are checked exceptions meaning that they must be handled at compile time (try-catch). Runtime exceptions themselves are unchecked exceptions you don't have to implement any logic to deal with them at compile time and they are discovered and handled at runtime.

28. Final vs Finally vs Finalize

Final is a non-access modifier that marks your variable as the value that it is initialized at forever, so a constant. Can also be applied to a class to make it so that no one can extend that class or a method to prevent subclasses from overriding that method. Finally refers to the finally clause in a try, catch, finally block. Finally will always execute, even if there is an exception. The only time that finally wouldn't happen is if you call system.exit or if there's a power failure or if you exit the application or anything that would be abnormal in the try/catch block. Finalize - a method that the garbage collector invokes when the JVM figures out that a particular instance should be garbage collected. The main purpose of using finalize is to release resources used by objects before they're removed from the memory. Programmers are strongly recommended to not override the finalize method because the garbage collector will panic and continue calling finalize on the object.

178. What is 1NF?

First Normal Form The lowest level of normalization. To be in 1NF a relation of the database is in first normal form if the domain of each attribute contains atomic values. This means that fields in the rows of the database can't be broken into smaller more logical parts and contains only one of these parts. Example could be street addresses : Use Street, city, state. Instead of address. 179. What is 2NF? Second Normal Form, one level of normalization higher than 1NF. To be in 2NF a relation of the database must first be in 1NF. To be in 2NF a relation must have all of it's attributes dependent on the relations primary key.

191. What do you need to get a JDBC Connection?

First you must have a configured driver. DriverManager loads the specified driver and gets a connection to the database. DataSource is an interface that's prefered to DriverManager because it allows some transparency for some parts of the datasource.

267. Is JavaScript Pass-By-Value or Pass-By-Reference?

For primitives javascript is pass by value. Javascript also uses call by sharing for objects. Call by sharing is similar to pass by reference in that the function is able to modify the same mutable object but unlike pass by reference isn't able to assign directly over it.

254. What tag would you use to create forms?

Form tag creates a form Input specifies the different form inputs Button or input type="button" can be used to submit. If there's only one button on the form it will default to the submit button.

329. Forward() vs SendRedirect()

Forward sends requests to other resources in the same server while SendRedirect sends requests to other resources in different servers Forward is declared in the the RequestsDispatcher interface while SendRedirect is declared in HttpServletResponse

270. What are functions in JavaScript?

Functions are objects to start A function object defines a series of tasks and/or calculates a value. Must be defined in the scope you wish to call it in.

292. What are the HTTP Methods?

GET - requests a representation of the specified resource. Get should only be used to get data. HEAD - asks for a response identical to that of a GET request, but without the response body. POST - used to submit an entity to the specified resource, often causing a change in state or side effects on the server. PUT - replaces all current representations of the target resource with the request payload. DELETE - deletes the specified resource. CONNECT - establishes a tunnel to the server identified by the target resource. OPTIONS - used to describe the communication options for the target resource. TRACE - performs a message loop-back test along the path to the target resource. PATCH - used to apply partial modifications to a resource. 293. What are the HTTP Statuses? 100 - info. 200 - success. 300 - redirect. 400 - bad request. 500 - server error.

342. doGet vs doPost vs GET vs POST.

GET and POST are HTTP protocols while doGet and doPost are methods specific to Java Servlet doGet is handles all GET requests while doPost handles all POST requests GET HTTP requests supplies all required data in the URL while POST HTTP requests supplies all required data in the request/message body

298. GET vs POST

GET requests can be cached GET requests remain in the browser history GET requests can be bookmarked GET requests should never be used when dealing with sensitive data GET requests have length restrictions GET requests should be used only to retrieve data POST requests are never cached POST requests do not remain in the browser history POST requests cannot be bookmarked POST requests have no restrictions on data length POST is NOT idempotent. So if you retry the request N times, you will end up having N resources with N different URIs created on server. PUT method is idempotent. So if you send retry a request multiple times, that should be equivalent to single request modification Idempotent - method can be called many times without different outcome

79. What are Generics for?

Generics enable types (classes and interfaces) to be parameters when defining classes, interfaces, and methods. They are used for type-checking at compile time, so that code will be more type-safe. Using Generics also eliminates the use of casts. An example of using Generics is in specifying the type of a Collection using diamond syntax.

269. What are the variable scopes in JavaScript?

Global, local, and block scope

477. How do you setup an AWS EC2?

Go to the AWS site sign in to the console go to the EC2 service page Click on instances then launch instance Select your AMI After the page reloads select your instance type (resources and purpose) Next click review and launch, make sure that everything you see is indeed what you want, then click launch Upon clicking launch you can generate an ssh key pair and save it somewhere safe because that's how you'll access the EC2. There will be some dialogue options for different setting configurations but you can click ok through all of those and configure them later Once you're done with that the instance will take a few minutes to spin up but your job is basically done.

243. HTML vs CSS

HTML defines the structure of a webpage while CSS defines the look

284. What are events?

HTML events are actions generated with user interaction with an element or elements. Good examples are click events on buttons, page loading, resizing the window, clicking links, hovering, etc. When a user does this with the mouse or keyboard the element can throw events to the javascript to work with or call predefined functions.

347. How does Error Handling work on JEE?

Handle the error on the server side with try-catch or throws Return status codes to the front-end depending on errors or lack thereof.

47. What are the types of sets?

HashSet LinkedSet TreeSet

81. Hashtable vs Hashmap

Hashtable - synchronized; doesn't allow null values for keys Legacy class that has been re-engineered to implement the Map interface Extends from Dictionary, an abstract class Hashmap - not synchronized (better for non-threaded applications; allows one null key and any number of null values Subclass of the AbstractMap class and a member of the Java Collection Framework right from the beginning of its introduction Doesn't guarantee the order of the map will remain constant over time

577. What're advantages of Hibernate over JDBC?

Helpful error messages Object Relational Mapping - change databases easily Reduces human error / stringification

494. What are the benefits to Hibernate?

Hibernate abstracts away some of the redundantness of JDBC. You don't need to program every DAO with Hibernate. Hibernate also has built in support for transactions and the sessions have built in methods such as get and load.

480. What is Hibernate?

Hibernate is an Object Relationship Mapping Framework/Tool. It allows a program to map a class to a relational database. In doing so, the programmer creates a sessionfactory. The sessionfactory contains the connection info for the database, as well as the driver, and dialect. You can map files either by a mapping file, or by JPA annotations in the classes you want mapped.

481. What does it abstract?

Hibernate is an abstraction of JDBC.

576. What is a transactional write-behind?

Hibernate uses a sophisticated algorithm to determine an efficient ordering that avoids db foreign key constraint violation, but it's still sufficiently predictable to the user

496. What is Hibernate.hbm2ddl?

Hibernate.hbm2ddl is a property you can set in the cfg that will tell hibernate whether or not to make the database. It is best not to use this in anything that isn't a development environment.

274. What is Hoisting?

Hoisting in javascript is when the interpreter moves all variable and function declarations to the top of the current scope. Only the declarations are hoisted, assignments are left where they are.

587. Contextual Session.

How you set up your Daos in Spring Repository Two approaches: Annotations - @Repository dao implementation class @Transactional Implement CrudRepository, JPARepository XML - Bind transactions to crud methods in application context How do you integrate Spring and Hibernate using Contextual Sessions?

241. What is the first tag in EVERY html file?

Html DOCTYPE

240. What are some common tags?

Html Head Body P Div Span h1 - h6 a Style Script Form Ul Ol Dl Li Dt Dd img etc.

337. What are the method signatures of doGet() and doPost()?

HttpServletRequest req, HttpServletResponse res

288. What is HTTP?

HyperText Transfer Protocol. The underlying protocol used by the world wide web. Defines how messages are formatted and transmitted, and what actions servers and browsers should take in response to various commands.

238. What is HTML?

Hypertext Markup Language Defines how a web page is laid out. Uses tags Know the format of tags.

213. What does a DATE subtraction return?

If you're using DATEDIFF() then it depends what you specify Can get the difference in years, quarters, months, days, weeks, hours, minutes, seconds, milliseconds.

258. What tag do you use to create an image?

Img Requires a src attribute which is where the image is from Also requires an alt attribute = specifies the alternate text for the image if it couldn't be loaded.

129. How do I make an object Serializable?

Implement the Serializable Interface Serializable is a marker interface (has no methods)

48. What is a HashSet?

Implements the Set interface; also implements Serializable and Cloneable Uses the hashtable as an underlying data structure Duplicate values are not allowed Objects that you insert in a HashSet aren't guaranteed to be inserted in the same order. Objects are inserted based on their hash code Hash refers to how you go and find the value. HashSet - only values, set of hashed values HashMap - key/values, map where the keys are hashed Collisions - update the older one

192. What are the steps to setup a JDBC Connection?

Import JDBC packages Load and register the driver Try with resources to get a connection from the driver manager or a class abstracting it. Create a statement object to perform a query. Execute the statement and retrieve the result set.

414. How do I include a Module into my application?

Import the module in your app module using import { modulename } 'module path'; Then list it as an import in the imports array of the NgModule After that you can inject it where you need it when/if necessary.

638. What is a SOAP Envelope?

Indicates the start and the end of the message so that the receiver knows when an entire message has been received

462. What is IaaS?

Infrastructure as a service A form of cloud computing that provides a virtualized computing resources over the internet.

21. What is Inheritance?

Inheritance is the concept that classes can share states and behaviors through extension. This relationship between classes is made between the parent or super class and the child or subclass.

53. What is an ArrayList?

Inherits AbstractList class and implements List interface Increases by half its size Constant time access Dynamically sized arrays Not thread safe Can only contain objects; not used for primitive types, but you can use a wrapper class for such cases

330. Context-Param vs Init-Param

Init-param is only accessible to the servlet that it is declared in while context-param is accessible to all servlets

229. All types of joins. You can get asked differences between any of them.

Inner Outer Left Right Natural Theta

164. What are the different types of Joins?

Inner Join - Returns data that occurs in both tables, only where there is a match in both tables Left Join - Returns the data that occurs in the left table and the values that matched records in the right table. Right Join - Returns the data from the right table and the matching data from the left table Full Outer Join - Returns all records from both tables and matches them when possible Self Join - Regular join where you join a table with itself Cross Join - Produces a result set in which the number of rows in the first table multiplied by the number of rows in the second table if no WHERE clause is used along with CROSS JOIN.This kind of result is called as Cartesian Product. 165. What are the set operators? Set operators combine the results of two component queries into a single result. Queries containing set operators are called compound queries. Include: UNION UNION ALL INTERSECT MINUS

226. INNER JOIN vs OUTER JOIN.

Inner join returns the matching data from two tables. Outer join returns the inner join along with the rows in the table which couldn't be matched.

113. InputStream vs Reader

InputStream is a byte stream (used for serialized data). Reader is a character stream (used for reading character data (files)). An InputStream can be changed to a reader using an InputStreamReader class

87. Which are the scopes of a variable?

Instance Only available to objects of the implementing class. Local Only available within the same block. Static Only available to the implementing class or block.

8. What are the types of variables?

Instance variable Local variable Static variable

7. What are the class members?

Instance variables Methods Constructors Inner class static/instance blocks

339. Servlet Hierarchy.

Interfaces Servlet ServletConfig Serializations GenericServlet HttpServlet UserDefinedServlet

327. What is a RequestDispatcher?

Is an interface that facilitates dispatching a requests to another resource. The RequestDispatcher provides two methods: Forward and Include

170. What is Isolation?

Isolation - ensures that the concurrent execution of transactions results in a system state that would be obtained if transactions were used sequentially. One transaction has nothing to do with any of the others.

325. What is the HttpServlet class? What methods does it provide?

It is a class that extends from the GenericServlet class and provides Http specific methods Provided methods: doGet doPost doPut doDelete service etc...

150. What is a Database?

It is a structured collection of data that is stored in a computer or server and can be accessed and manipulated in various ways.

144. What is DDL? What are the keywords?

It stands for Data Definition Language and it is used to define tables and set their properties. With it, you can create a table, alter the properties of the table and drop the table. The keywords are CREATE, ALTER, DROP, TRUNCATE

140. What is an RDBMS?

It stands for Relational Database Management system which is a program that allows you to create, update, and save data in a relational database. Some examples are Oracle, PostgreSQL, MySQL, SQLite.

44. What is a Collection?

Iterable -> Collection -> Set, List, Queue Collection - interface Collections - utility class that has static methods for doing operations on objects of classes which implement the Collection interface

108. What does the Iterable interface do?

Iterable is a marker interface meaning that it marks the implementing class as iterable allowing it to be iterated through. Allows the class to use a for-each loop iterator() - returns an iterator for the object.

299. What is J2EE?

J2EE stands for Java Platform Enterprise Edition. It is a collection of Java APIs used to write server-side applications.

190. What is JDBC?

JDBC - Java Database Connectivity. An API specification for connecting java programs to popular databases Done using a driver for the particular dialect.

519. What are the Cascade Types?

JPA Cascade Type All - shorthand for 'all of the above cascade operations' Remove - delete the child when the parent is deleted Refresh - same thing as the refresh operation Persist - save or persist operations cascade to related entities Merge - related entities are merged when the owning entity is merged Detach - detaches all related entities if a manual detach occurs Hibernate Cascade Type

276. JSON vs JS Object

JSON is JavaScript Object Notation JSON is a data interchange format, a way to pass structured information between languages. JSON is formatted similarly to how a JavaScript Object is formatted which makes it very easy to parse and build objects from.

286. What are the JSON conversion types?

JSON to DataObject conversions: String JSON can convert to string, long if long value , double if double value, boolean if true or false, date/datetime if is a date value. Long to string, long, double, or date if value is a date. Double to string, long if long value, double. Boolean to string and boolean.

138. Which version of JUnit have you used?

JUnit 4-5

617. What is JAX-WS?

Java API for XML Web Services (JAX-WS) is one of a set of Java technologies used to develop Web services.

4. JDK vs JRE vs JVM

Java Development Kit contains compiler and debugger tools to compile the Java source code, also includes Java Runtime Environment and Java Virtual Machine The JRE provides an environment and in that environment the JVM runs the compiled byte code. It contains both the library and the JVM. The JVM creates a layer of abstraction from the Java Code and the computer environment. It is used to convert the java bytecode into machine readable code.

98. Some concrete implementations of Set.

Java has three general purpose ones. HashSet Methods: Add - adds an element to the set if it's not already present Clear - removes all elements from the set. Clone - returns a shallow copy of the hashset (elements themselves are not cloned) Contains - returns true if set holds the specified element isEmpty - returns true if the set is empty. Iterator - returns an iterator over the elements of this set. Remove - removes the specified object from the set if present. Size - returns the cardinality of the set. TreeSet - Combination of Tree and Set. (more sortable) Methods: Add - adds specified element if it doesn't exist. addAll - adds the contents of a collection to the set. Ceiling - returns the least element of the set that is greater than or equal to the specified element, or null if no such element can be found. Clear - removes all elements from this set. Clone - returns a shallow copy of the set. Comparator - returns the comparator used to order the elements of this set or null if using natural ordering. Contains - returns true if this set contains the specified element. descendingIterator - returns an iterator over the elements in descending order. descendingSet - returns a reverse order view of the elements in the set. First - returns the lowest element in the set. Floor - returns the greatest element in the set that is less than or equal to the element, or null if it doesn't exist. headSet - returns a view of the portion of this set whose elements are less than (or equal to) to the specified element. Higher - returns the lease element in this set that is strictly greater than the element or null if DNE. isEmpty - returns true if set is empty Iterator - returns an iterator over the elements in ascending order. Last - returns the highest element currently in the set. Lower - returns the greatest element in the set strictly less than the given element, or null if DNE. pollFirst - retrieves and removes the lowest element, or returns null if empty. pollLast - retrieves and removes the highest element, or returns null if empty. Remove - removes the specified element if present. Size - returns the cardinality of the TreeSet. Subset - returns a portion of the set whose elements range from the lowest specified to the highest specified. tailSet - returns a view or portion of the set greater than or equal to if inclusive is true to the specified element.

259. JavaScript and AJAX

JavaScript is an object oriented interpreted scripting language Used on web pages for DOM manipulation to make the pages more interactive. AJAX Stands for Asynchronous JavaScript and XML. A new technique for creating better, faster, and more interactive web applications using XML, HTML, CSS, and JavaScript.

263. Is JavaScript loosely typed or strict typed?

JavaScript is loosely typed you don't declare the data types of variables explicitly.

278. What does it mean to be "Falsy"?

Javascript doesn't use true and false when doing logical comparisons JavaScript uses type coercion, truthy is not just the value true, it's values that could logically represent a true value. Truthy values could be true, empty object, empty array, empty function, positive numbers, and non empty strings Falsy values could be false, null, undefined, NaN, zero, and empty strings.

264. What kind of compiler does JavaScript use/have?

Javascript is interpreted not compiled The script is interpreted by other applications like web-browsers or npm.

440. What is Jenkins?

Jenkins is a continuous integration and/or delivery environment. Runs on a server, uses hooks to pull code from a repository when the code is pushed, and it will run the tests and provided they pass it can then deploy it, depending on the implementation.

110. Can I sort a Map? (AHHHH)

Kinda There's typically no need to sort a map because values are found by unique keys It's possible to do if the keys or the values within them are sortable.

502. What are the different fetching types?

Lazy Fetching and Eager Fetching

578. Different kinds of fetching

Lazy fetching - fetched when needed; used in conjunction with joins Lazy initialization exception Eager fetching - fetched at the start; automatically joins

332. Eager Loading vs Lazy Loading

Lazy loading - a servlet is not loaded when server is starting and load only when the servlet receives a request Eager Loading - servlet loads while server is starting A servlet can be set to load eagerly when you declare <load-on-startup>

361. What does the "let" keyword mean?

Let is similar to var in some respects but let forces local scoping that var can cause problems with.

290. What are other commonly used XML HTTP methods?

Look above...

214. LEFT JOIN vs MINUS.

MINUS is a keyword in some sql dialects and it works like A-B in sets. MINUS would return everything in set A that are not found in BOTH A and B. LEFT JOIN = (A MINUS B) + (A INNER JOIN B).

612. Set up Application Context

New Application Context XML files ClasspathXMLApplicationContext FilesystemXMLApplicationContext WebXMLApplicationContext Annotations - mark it @Configuration; each bean mark @Bean AnnotationConfigApplicationContext

289. What are the Xml Http Request methods?

New XMLHttpRequest() - creates a new XMLHttpRequest object. abort() - cancels the current request. getAllResponseHeaders() - returns header information. getResponseHeader() - returns specific header information. open(method, url, async, user, psw) - specifies a request. send()/send(string) - sends the request to the server. setRequestHeader() - adds a label/value pair to the header to be sent.

277. What does the keyword "STRICT" mean?

New as of ES5. Is a literal expression indicates that the code should be executed in "strict mode" In strict mode you can't do a lot of things that you can do outside of un-strict mode, for example using undeclared variables.

426. How do I bundle my Angular application?

Ng build command for the cli will bundle the application into a dist/ folder Specifying a production built with --prod will be more optimized for user interaction Not specifying production will not be optimized but it will be enough to pass around the development team.

401. CLI commands to generate components and services.

Ng g c component-name - generates a component. Ng g service service-name - generates a service.

376. What is ngModel?

NgModel is an Angular Directive Creates a FormControl instance form a domain model and binds it to a form control element. The FormControl instance will track the value, user interaction, and validation status of the control and keep the view synced to the model. Can be used by itself or as part of a larger form, if so it will also register itself with the form as a child control. Often used to achieve two-way databinding.

88. Can you override static methods?

No Static methods are not associated with class instances so overriding is not applicable. Static methods of a class cannot be accessed by its objects only the implementing class.

3. Is Java 100% Object Oriented Programming? Why or Why Not?

No because of primitives which are not objects

410. Is it mandatory to export every component?

No but if you don't export it you can't import it into any other component that needs it.

75. Can I force garbage collection?

No, you can't force the garbage collector to scan the heap. The garbage collector starts when the first user thread is started by the JVM, and it is terminated when the last user thread terminates. You can invoke the method (System.gc) to run the garbage collector, but it does NOT guarantee that the garbage collector will run. The JVM is in charge of when a thread will run, and the garbage collector is a thread.

177. What is Normalization? What is it used for?

Normalization is the process of organizing the database into different forms each with their own sets of rules. Makes the database more consistent and safe. There are several normal forms. Minimize data redundancy, reduce duplicate data

49. What is a SortedSet?

Not ordered Implements the Comparable interface All elements must be mutually comparable - compared elements accept each other as the argument to their compareTo method Can be sorted in a natural order with Comparable interface or using a Comparator

356. What is a thread pool?

Object pools are used in java for storage of objects that we want to use dynamically. The thread pool is one of these object pools Object pools controls the lifecycle of its resources. Many of the java.util.concurrent libraries use thread pools implementing thread pools of worker threads Worker threads are separate objects from Runnable and Callable tasks and are usually used for multiple tasks.

562. Hibernate exceptions.

ObjectNotFoundException - load LazyInitializationException - with lazy, you have to do a join in the query otherwise the referencing object won't be available to query later and you'll get the lazy initialization exception OptimisticLockException - detects conflicting update of an entity at the same time UnknownIDGenerator QuerySyntaxException

151. What are Objects in SQL?

Objects in SQL are any defined object that can store or reference data. Some objects may encompass other SQL objects The database itself is a SQL object itself that encompasses all other data objects The database contains Schema objects that contain table objects and views Columns are the smallest data object

122. What is hashCode() for?

Objects.hash(Object... values) should be used in cases when you want a hash of a sequence of objects, e.g. when defining your own hashCode method and want a simply-coded hash for multiple values that make up the identity of your object. Objects.hashCode(Object o) should be used when you want the hash of a single object, without throwing if the object is null. Object::hashCode() should be used when you want the hash of a single object, and will throw an exception if the object is null.

160. What are the different relationships in SQL?

One-to-one - both tables can have only one record on either side of the relationship. One-to-many - one table can only have one record on its side of the relationship while others can have many records of the relationship Many-to-many - both sides can have many records on either side of the relationship.

715. Explain Spring Boot.

Opinionated view of the Spring platform to make it easy to configure Spring applications for various use cases.

701. How to implement the Orchestration service?

Orchestration the process of integrating two or more applications and/or services together to automate a process Call to a WebService Retrieve additional information from a secondary service or API Store the result in a DB or handle the information how you want to

185. GROUP BY vs ORDER BY

Order by alters the order in which items are returned, essentially just sorting the result set. Group by will aggregate records by the specified columns which allows you to perform aggregation functions on non-grouped columns.

112. What is Starvation?

Part of the producer consumer problem Occurs when two threads are sharing resources producer is producing resources and the consumer is consuming them When the producer produces so fast that the consumer can't keep up it reaches a point where it can no longer produce causing it to starve on runtime The same thing happens when a consumer is consuming faster than a producer can produce, it reaches a point where it isn't efficiently receiving data also causing starvation.

725. What is PCF?

Pivotal's implementation of CF Platform As A Service - only have to upload your application; don't have to set up your environment

427. What does TypeScript transpile into?

Plain JavaScript

461. What is PaaS?

Platform as a service A category of cloud computing services that provides a platform for customers to develop run and manage applications without the complexity of developing the infrastructure associated with developing and launching an application.

607. JoinPoint vs Pointcut.

Pointcut - point of execution in which a cross cutting concern needs to be applied Joinpoint - where you're looking for your pointcut

18. What is Polymorphism?

Polymorphism is the concept that in Java, objects can have the same states and behaviors, so they are interchangeable. The JVM will determine the program's intentions at runtime or compile time. This refers to runtime polymorphism and compile time polymorphism. Runtime polymorphism is also known as dynamic polymorphism, and an example of this is method overriding. Method overriding is runtime polymorphism because at runtime, the JVM will go look for the method from parent to child class based on the override annotation. If the method signature matches, then it will use that, otherwise it will go look for the parent's method. Method overloading is compile time polymorphism. At compile time, assuming there is more than one method with the same method name, the JVM will find the appropriate method based on the return type and parameter list.

248. What are Meta Tags?

Provide metadata about the HTML document. Metadata will not be displayed on the page, but will be machine parsable. Meta elements are typically used to specify page description, keywords, author of the document, last modified, and other metadata.

322. What is MVC?

Represents Model, View, Controller MVC is an architectural pattern that separates an application into three main components: Model - all data related logic View - all UI related logic Controller - handles all business logic and incoming requests.

261. What is OBP?

Represents Object Based Programming. Basically a superset of OOP.

592. What is Spring MVC?

Request from client Dispatcher Servlet- Servlet that listens to all incoming HTTP Requests - Integrated with Spring IoC container Handler Mapper - searches for controllers @Controller or @RestController @RequestMapping - url, data types @RequestBody View Resolver for Controller Data only for RestController @PathVariable - if the param is called the same name as the path param, you don't need the extra definition Purpose: identify a specific object (ie id 1) @RequestParam (query param) Purpose: use for filtering (ie. searching for all blue suits, query param = blue)

83. Thread methods. (run, start, sleep, wait, notify, notifyAll, join).

Run - Executes starts the thread of execution. Start - Creates a new thread and calls run(). Sleep - static method of a thread, doesn't release resource locks. Wait - method of an object, releases resource locks. Notify - wakes up only a single thread from a wait state to use a resource. NotifyAll - wakes up all threads waiting for a resource. Join - causes the current thread to wait for another thread to finish.

84. Difference between the run and start method?

Run is a method of an object calling runnable Start is a method of an object inheriting from the Thread class When you call run it executes the run method. When you call start it instantiates a new thread and calls run.

237. - How would you get the top 5 salaries from every department? (All departments are in ONE table)

SELECT * FROM employees ORDER BY salary DESC LIMIT 5

236. How would you get the minimum salary from every department? (All depts are in ONE table)

SELECT MIN(salary) AS "Lowest salary" FROM employees GROUP BY department;

688. What protocols does SOAP allow?

SOAP can operate over any protocol. Microservices

655. What is the basic structure of SOAP 1.1

SOAP envelope SOAP header (optional) Header Block(s): used to pass application-related information that is to be processed by SOAP nodes SOAP Body (mandatory) SOAP Fault: Used for errors Body subelement: Used for information for the recipent of the message

650. What is SAAJ?

SOAP with Attachments API for Java Used to make Java API calls that generate XML messages which comply with the SOAP 1.1 or 1.2 specifications, as well as the WS-I Basic Profile 1.1 specification

646. How do you consume a Web Service?

SOAP: Create classes to represent our complete data types Create an interface with all the same methods as the Services JAXWSProxyException - Used to create an object which implements our SEI Calling any of our methods in our SEI will invoke their implementation in the SIB on the Source

727. What are some things you would want in a cloud platform?

Scalability Security and integration Self-healing Statistics / Metrics Logging Application Lifecycle Portability

451. What is SCRUM?

Scrum is the practice of the agile strategy Agile is the idea, scrum is agile in practice. In Scrum there is a scrum master who holds meetings to track the progress of the sprint The scrum master also breaks the sprint into features and assigns them points according to difficulty Team members pick features to work on and their work is classified from in progress, to testing, to fixing or debugging, and finally to complete/finished. Finished features are pulled to the staging branch which will run a set of integration tests and deploy.

199. What is a nested query?

See subquery.

623. What is Code-On-Demand?

Sending static representations of resources in forms of XML or JSON.

40. What is Serialization?

Serialization is the process where java objects are converted to byte streams Serialization is for transferring objects from Java to Java applications only. Serialization (object to stream) and deserialization (stream to object) Must use the serializable interface to be marked for serialization Transaction Isolation Level Invalid class exception Not serializable exception Class not found exception

689. Main advantages of using microservices.

Services are independently deployable and scalable It allowing for different services to be written in different programming languages. Scalability and reusability Work well with containers such as Docker Better fault isolation; if one microservice fails, the other will continue to work Handling traffic well - instances of services created as needed Loose coupling

333. Servlet Context vs Servlet Config

Servlet Config - are specified only for a particular servlet and is used for initialization purpose Servlet Context - are specified for the entire application and is accessible by all servlets within that application

345. Servlet Context vs Servlet Config. How do you write it on the web.xml?

Servlet Context - <context-param> Servlet Config - <init-param>

303. What is the Lifecycle of a Servlet?

Servlet class is loaded Loaded when the first request for the servlet is received by the web container Load on startup Servlet instance is created Created after the servlet class is loaded. Created only once in the servlet life cycle. Init method is invoked Web container calls the init method once after creating the servlet instance. Used to initialize the servlet. Service method is invoked Called every time a request is received for the servlet Destroy method is invoked Called before removing the servlet instance from the service. Used to clean up any resources

302. What is a servlet?

Servlet is a technology used to create web applications; it is used to respond to incoming requests.

97. What is the difference between a List of a Set?

Set values need to be unique

135. Why do we test software?

Several reasons, Testing is very important in all phases of development. Unit Testing Make sure methods/functions are working properly. Not meant to catch bugs Regression Testing New features don't break old ones BDD - behavior driven Integration Testing Make sure new code is compatible with the existing code base Complete system testing Stress Testing Make sure you application can perform well with large loads of traffic or large calculations. Acceptance Testing Make sure end users like the new state of the application. Easy to understand Are user needs fulfilled? Compliance Laws Etc. There's a lot of tests.

89. What is shadowing?

Shadowing is when two variables or objects with the same name and type have overlapping scopes. When this happens the field with the larger scope is hidden.

91. What is Varargs used for?

Short for variable length arguments When a method can have any number of parameters and overloading the method would cause too much ambiguity. So you can pass ellipses into the parameter of your method after the first argument and then access the varargs array. Varargs is an array of arguments that is an array of data passed in when a method is called, args is the array containing all the parameters passed into the function.

572. What's the difference between sorted and ordered collections?

Sorted - natural ordering; use it for smaller collections; expensive to sort Ordered - use it for larger collections; specify by the ORDER BY clause Collections - resultset

574. Spring Modules

Spring Web This group comprises of Web, Web-Servlet, Web-Struts and Web-Portlet. These modules provide support to create web application. Spring Core These modules provide IOC and Dependency Injection features. Spring Context This module supports internationalization (I18N), EJB, JMS, Basic Remoting. Spring Data This group comprises of JDBC, ORM, OXM, JMS and Transaction modules. These modules basically provide support to interact with the database. Spring Security a powerful and highly customizable authentication and access-control framework. It is the de-facto standard for securing Spring-based applications. Consist of: Kerberos, OAuth, SAML Spring AOP Aspects are the unit of modularity, rather than objects in OOP An aspect is a common feature that's typically scattered across methods, classes, object Spring MVC Module of spring which gives us the ability to handle HTTP requests Model,View,Controller Model is your data View is the frontend Controller connects the two

575. Bean Lifecycle.

Spring finds bean definition Instantiate Populates properties using dependency injection If the bean implements bean name aware -> set bean name Bean factory aware - make the factory aware of the bean -> set bean factory Pre init Post processor Init Custom init Ready - being used Destroy Custom destroy Finalize

577. ApplicationContext vs BeanFactory.

Spring's IOC containers Bean Factory - The BeanFactory is the actual container which instantiates, configures, and manages a number of beans. These beans typically collaborate with one another, and thus have dependencies between themselves. These dependencies are reflected in the configuration data used by the BeanFactory(although some dependencies may not be visible as configuration data, but rather be a function of programmatic interactions between beans at runtime ApplicationContext - supports Spring's newer modules; eager initialization for beans (can also tell it to do lazy initialization); includes new features such as messaging While the beans package provides basic functionality for managing and manipulating beans, often in a programmatic way, the context package adds ApplicationContext, which enhances BeanFactoryfunctionality in a more framework-oriented style. Many users will use ApplicationContext in a completely declarative fashion, not even having to create it manually, but instead relying on support classes such as ContextLoader to automatically start an ApplicationContext as part of the normal startup process of a Java EE web-app. Of course, it is still possible to programmatically create an ApplicationContext.

194. What are the different types of Views?

Standard views Combines data from one or more tables through a query. Indexed views A view that has been computed and stored. A view is indexed by creating a unique clustered index on it. Dramatically increases performance on some types of queries. Partitioned Views Joins horizontally partitioned data from a set of member tables across one or more servers.

456. What is AWS?

Stands for Amazon Web Services A secure cloud services platform Offers a ton of services for: Cloud computing Storage Databases Migration Management tools Mobile services Customer Engagement Business Productivity Machine Learning Analytics Desktop and App streaming IoT Game Development Etc.

198. What are the C.R.U.D operations?

Stands for Create, Read, Update, and Delete. They are the four basic functions of persistent storage.

193. What is DAO?

Stands for Data Access Object The interface for your database Establishes connections and executes queries sent to it. Passes result set.

312. What is XSL?

Stands for Extensible Stylesheet Language Describes how XML elements should be displayed Consist of three parts: XSLT - language for transforming XML documents XPath - language for navigating in XML documents XSL-FO - Used for formatting XML documents

314. What is XSLT?

Stands for Extensible Stylesheet Language Transformations Used for transforming XML documents into other XML documents Ex: HTML to XHTML

305. What is XML?

Stands for extensible markup language It defines set of rules for encoding documents in a format that is both human-readable and machine readable

624. What is the lifecycle of a Service?(Possibly incorrect)

Start Service: Service is called to start Service is created on call Service is started on call Service is stopped naturally by itself or by client *(optional)*Service onDestroy() is called freeing up Bind Service: Service onCreate is called Service onBind called Clients are bound to service Clients unbindService called onUnbind() *(optional)* Service onDestroy

218. Statement vs PreparedStatement.

Statement is vulnerable to SQL injection in which an attacker could finish a query logically and end it with a semicolon and start another query that could potentially harm the database (Bobby Tables). Prepared statements are not vulnerable to sql injection they preload the database with a query and then send in expected values after which are cast to strings and placed into the query. 219. DROP vs DELETE. DROP is a DDL command that removes it's arguments from the table or removes the whole table from the database. DELETE is a DML command that removes the values from the columns matching it's arguments.

11. What are the Non-Access Modifiers?

Static - variable or function is shared between all instances of that class as it belongs to the type, not the actual objects themselves Final - define an entity that can only be assigned once. Once a final variable has been assigned, it always contains the same value. Abstract - purpose of extending Synchronized - used for threads; accessed by only one thread at a time Volatile - used for threads; lets JVM know that a thread accessing a variable must merge its own private copy with the master copy in memory Transient - used in serialization; field that is transient won't be sent at all and will appear as null on the other end

29. What does the keyword "Static" mean?

Static is a non-access modifier that means you can use that method or variable from a class without instantiating that class. Static also means that it belongs to the class itself and not an instance of a class. For static variables there's 1 shared copy of the variable among all instances of the class and static methods can only use static variables.

442. Where are Maven Dependencies Stored?

Stored in a configuration file called the pom Pom is an xml file Pom stands for project object model.

37. String vs StringBuilder vs StringBuffer

String - Immutable (cannot be changed or extended); stored in string pool; thread safe StringBuilder - Mutable; for strings changing rapidly; do not extend string because string is final StringBuffer - Mutable; synchronized, much slower; do not extend string because string is final; thread safe, useful for threads/strings being manipulated by multiple threads

94. What is the difference between StringBuilder and Buffer?

String builder is unsynchronized; faster String buffer is synchronized; slower

106. What makes the String class special?

Strings can be created with literals Strings created with literals are stored in the string pool Strings created with new are stored in the heap

360. Is Typescript Loosely or Strongly Typed?

Strongly typed Or loosely typed (any is a type)

130. What is your experience with JUnit?

Test Driven Development JUnit 4-5 Mocking with Mockito

487. What are the Hibernate Object States?

The Hibernate Object States are: Transient - Object exists outside of session and the row Persistent - Object in the session that represents a row in the database Detached - Object is removed from the session, any actions on the object are not saved to the database.

326. What is the flow of client-to-server using a servlet?

The client sends requests through HTTP over TCP/IP to the HTTP server. The servlet will receive the HTTP requests and return a response back to the client.

453. What is the Waterfall Methodology?

The development lifecycle for an entire application An alternative to the agile methodology. Instead of breaking up the application into features and sprints it breaks the development process up into steps. Steps are: System engineering Analysis Design Code Testing Maintenance All steps must be completed one at a time, you can't go to the next step until the entire application is finished on the step before. you have to go all the way to the bottom of the chain before you can go back up to the top and make a new application or version. Typically less favored in software development because the pace.

77. What is the finally block?

The finally block is the block that executes after a try-catch block. A finally block will always execute, even if an exception is thrown. A finally block won't execute when the system exit method is invoked, if the power goes out, or any other extreme circumstances occur.

319. What is Unmarshalling?

The process of transforming a representation of an object that was used for storage or transmission to a representation of the object that is executable.

318. What is Marshalling?

The process of transforming the memory representation of an object to a data format suitable for storage or transmission

574. What is a hibernate proxy?

The proxy attribute enables lazy initialization of persistent instances of the class

691. Dependencies of Microservices (what do we need to use).

a) Eureka (Discovery). client side discovery pattern client obtains the location of a service instance by querying a service registry, which knows the locations of all service instances. Ribbon creates requests by load balancing algorithms b) Zuul (Gateway). Zuul acts as an API gateway. It receives all the requests coming from the UI and then delegates the requests to internal microservices. The client calls this service as a proxy for an internal microservice, then this service delegates the request to the appropriate service The advantage of this type of design is that common aspects like CORS, authentication, and security can be put into a centralized service. we can implement any routing rules or any filter implementation c) Configuration Server. Configuration server to centralise management of all the configuration files mainly responsible for providing properties files to each microservice connected to the discovery server ex) if we need to update just a username for a database in property file, we need to first locate where the module is stored, then go to that server, change the property for that module and rebuild the whole module. In microservices, there will be a huge number of modules so it is very difficult. so In microservices, a new layer has been introduced to manage all things related to properties files. d) Kafka (Messaging). Apache Kafka is an open-source stream processing software platform For scale-out and high availability broker architecture with cluster = broker Consumer pull from the broker (other message system is broker push to consumer) The project aims to provide a unified, high-throughput, low-latency platform for handling real-time data feeds. 4 major API in Kafka Producer API Consumer API Connector API Streams API e) Hystrix (Monitoring). Circuit breaker module wrap a protected function call in a circuit breaker object, monitors for failures,. and when it happen it trips and further calls to circuit breaker return an error without call being made at all. This will prevent cascade error across multiple system by run out of critical resources. f) Docker (Orchestration). Docker is software which lets you create an image(template for virtual machine)

641. What is SoapUI?

an easy-to-use graphical interface and enterprise-class feature. It allows you to easily create and execute automated functional tests, regression and load tests.

619. What is JERSEY?

an open source framework for developing RESTful Web Services in Java. It provides support for JAX-RS APIs and serves as a JAX-RS Reference Implementation

601. Cross Cutting Concerns.

concern which is applicable throughout the application and it affects the entire application Logging - needing access to certain variables in that class

335. getParameter() vs getAttribute()

getParameter - returns the HTTP requests parameters passed from client to server getAttribute - mostly for server-side usage only; filling a request with attributes that can be used within the same requests. Ex: set an attributes within servlet and read it from a JSP

392. What are the Lifecycle Hooks?

ngOnChanges - called when an input binding value changes ngOnInit - after the first ngOnChanges ngDoCheck - after every run of change detection ngAfterContentInit - after component content initialized ngAfterContentChecked - after every check of component content ngAfterViewInit - after component's view(s) are initialized ngAfterViewChecked - after every check of a component's view(s) ngOnDestroy - just before the component is destroyed 393. What are the data types in Angular? None, Angular is a framework.

620. What is an Endpoint?

one end of a communication channel Temporary Credential Request URI (called the Request Token URL in the OAuth 1.0a community spec). This is a URI that you send a request to in order to obtain an unauthorized Request Token from the server / service provider Resource Owner Authorization URI (called the User Authorization URL in the OAuth 1.0a community spec). This is a URI that you direct the user to to authorize a Request Token obtained from the Temporary Credential Request URI. Token Request URI (called the Access Token URL in the OAuth 1.0a community spec). This is a URI that you send a request to in order to exchange an authorized Request Token for an Access Token which can then be used to obtain access to a Protected Resource.

118. What's the first line in a constructor?

super()

621. What is Idempotent?

the operation a number of times, but the resulting state of one call will be indistinguishable from the resulting state of multiple calls

324. What are the important tags you need to include in the web.xml?

web-app servlet, servlet-name, servlet-class servlet-mapping, servlet-name, url-pattern init-param, param-name, param-value context-param, param-name, param-value

239. What is the extension to an HTML file?

.html

291. What are the Ready States in HTTP?

0: request not initialized 1: server connection established 2: request received 3: processing request 4: request finished and response is ready

444. What are the Maven Lifecycles?

3 lifecycles Default Build Clean Site

331. What are the important tags you need to include within Context-Param and Init-Param?

<param-name> and <param-value>

390. What is CDN?

??????

372. What are some common decorators?

@Component @NgModule @Input @Output @Inject

116. What is an Abstract class?

A class that cannot be instantiated.

320. What is a Front Controller?

A design pattern that represents a single controller that handles all incoming requests

272. What is an anonymous function?

A function that is created at runtime. The function operator can be used anywhere that it's valid to use an expression. Called "anonymous" because the function was not "named"

69. How do you invoke a static method?

A static method can be invoked within the class that it is declared in without needing to create an instance of that class to invoke the method. Outside the defining class, a static method is called by prefixing it with its class name. It can also be qualified with an object, which will be ignored, but the class of the object will be used.

479. What is resiliency?

A systems capability to handle disaster such as weather, power, or other catastrophe that can affect the systems and their services so that the application can stay available to users.

405. What is a template?

A template is a scaffold for how something is supposed to look or act. In angular 4 you can define HTML templates for the applications components, you can define template contexts in interpolation expressions and many other things. You can load the templates into the application using the ng-template tag.

59. What is a Thread?

A thread is a part of a process that runs a path of the program in execution. It runs asynchronous to the main method thread. When your program starts up, at least one thread is created by the JVM, which is the main method thread. Another example of a thread is the garbage collector.

359. What is Typescript?

A very high level view Typescript is a superset of javascript which primarily provides the option of static typing, classes, and interfaces. Typescript is a transpiled language that is open source. Typescript is compiled into javascript to be served on a webpage Typescript adds a lot of benefits to what javascript is while still being familiar to javascript users Benefits include: Optional static typing and type inference. Enhanced IDE support. Strict null checks. JavaScript interoperability. Typescript also has many frameworks such as angular, Aurelia, Ionic, NativeScript to name a few, built on top of it for even more added functionality.

470. What is a Security Group?

A virtual firewall that controls the traffic for one or more instances. When an instance is launched you associate a security group to it for it to filter traffic down to only IPs matching that group.

395. What are template literals?

A way of assigning strings. They are defined between two backticks `` and variables can be inserted with ${var} without having to break the strings and do concatenation. Another benefit is that they support multiline

611. What is a Web Service?

A web service is any piece of software that makes itself available over the internet and uses a messaging system. Web services are self contained, modular, distributed, dynamic applications that can be described published, located, or invoked over the network to create products, processes, and supply chains. These applications can be local, distributed, or web-based. Uses a standardized XML messaging system at the very least.

184. WHERE vs HAVING

A where clause is used to filter records form a result, the filter happens before any query is done. Having clause is used to filter an already existing group, having filters results from a completed query.

167. What are the Transaction Properties?

ACID. Atomicity. Consistency. Isolation. Durability.

474. Region vs Availability Zones

AWS Regions are a separate geographical area and has multiple isolated locations that are availability zones Availability zones are the locations that are available to put instances For example US East is a region, and Ohio and N. Virginia are availability zones.

16. How do you achieve Abstraction?

Abstract class Using a framework, such as Spring

73. Can I0 instantiate an Abstract class? Constructor?

Abstract classes can't be instantiated, but they can be subclassed. Abstract classes do have constructors, and those constructors are invoked when a concrete subclass is instantiated.

14. What are the 4 pillars of Object Oriented Programming?

Abstraction Encapsulation Inheritance Polymorphism

15. What is Abstraction?

Abstraction is focused on the concept of reusability which is achieved using generalization or specialization. In abstraction, the programmer's focus is what happens, rather than the implementation. An example of abstraction is using abstract classes. To reiterate the point of generalization and specialization, an abstract class provides general states and behaviors that can be overridden by classes that extend it, thus creating a unique implementation of that abstract class.

450. What is Agile?

Agile is a development strategy based on the idea of incremental delivery using technology such as continuous integration, development, delivery, and deployment. The strategy is to break the application into a set of features and add features to the basic application in a series of sprints to build the software overtime. Using continuous integration and deployment tools sprints can go very fast and helps detect bugs and problems as you go making bug fixing quicker.

162. What is a Unique Key?

Also called a unique constraint. A unique constraint can be used to insure that there is no duplicate data in the rows of the table.

249. What is ASCII?

American standard code information interchange A character encoding standard for electric communication.

245. What is iFrame?

An HTML document embedded inside another HTML document on a website. The IFrame element is used to insert content from another source, like an ad on a web page.

348. How does the Servlet Container track sessions?

An HttpSession object can be created by invoking the requests getSession() method. Sessions in servlets manage user sessions; used with JSPs and JSFs because they have views, meaning they serve as both the client and server; not with RESTful servlets

182. What is an Aggregate Function?

An aggregate function is a function where the values of multiple rows are grouped together to form a single value of more significant meaning or measurement. An aggregate function takes data and returns an interpolation from that dataset. Examples: average() count()

105. When is an object ready for garbage collection?

An object is ready for garbage collection when there's no longer any reference to it in memory. This typically happens in when the object goes out of scope.

260. What is JavaScript?

An object oriented computer programming language commonly used to create interactive effects within web browsers.

230. What is an index?

An on-disk structure associated with a table to speed up row retrieval (table of contents).

256. What does attribute 'target="_blank"' do?

Anchor links may have the target attribute which controls what happens when the anchor is clicked. If the target is _blank this tells the browser to open a new window (or tab depending on user settings) when the link is clicked.

52. What are the types of lists?

ArrayList LinkedList Vector Stack

381. How do you make asynchronous calls using Angular?

Assuming you're using a service with a predefined function that is returning an observable or a promise. Make the call to the service and subscribe to it with the subscribe method. Inside the subscribe method i would define a callback to execute when the service call is resolved and inside that you can store it in a variable or do any manipulation you want.

206. CLOB vs BLOB.

BLOB: Variable-length binary large object string that can be up to 2GB long Primarily intended to hold non-traditional data such as voice or mixed media. BLOB strings are not associated with a character set. CLOB: Variable-length character large object string that can be up to 2GB long. Can store single-byte character strings or multibyte, character-based data. Considered a character string.

573. Collections you can use in hibernate

Bag - retrieved randomly Array Map Set List

71. How many objects on the heap if I cast?

Because casting an object won't create another object in the heap, there will only be that one object in heap plus whatever else was already existing in the heap.

603. Advice.

Before After (Finally) After Returning After Throwing Around

134. Difference between @BeforeClass and @Before?

Before runs before every test Before class runs once before the class is run.

400. What are the data types in Typescript?

Boolean String Number Array Enum Any Void

634. What do you need to make a REST application into a RESTful service?`

Build a service to accept a HTTP request JSON representation of that information to receive and send Optional: You can add a name parameter to a string to the request to specify information

434. What is CI?

CI is short for continuous integration Continuous integration is a development practice that requires developers to integrate code into a shared repository several times after a period called check-ins, these check-ins take pushed code and run an automated build to find problems early The growing code base becomes more efficient with integrating new features and fixes, hence the name continuous integration.

70. What is casting?

Casting is the process of taking an object of a particular type and turning it into another type, which gives you access to that type's methods. Casting is used when going from a more general to specific type. For example, Integer inherits from Number, so if you want to store an Integer as a Number, that's okay, since all Integers are Numbers. But if you want to go the other way around, you need a cast, since not all Numbers are Integers.

34. Checked vs Unchecked Exceptions

Checked Exceptions - fall under Exceptions; must be thrown or surrounded in a try/catch block otherwise the JVM won't compile the code. Outside resource failing. Exception, IOException, FileNotFoundException, SQLException Unchecked Exceptions - fall under RuntimeExceptions, which is a subclass of Exception. Unchecked Exceptions can be compiled and will throw an exception at runtime. Unchecked exceptions can be caught or handled with logic. RuntimeException, ArrayIndexOutOfBoundsException, ArithmeticException

9. What are the scopes of the variables?

Class - inside class Method - inside method Block - inside for or if statements

632. What are some benefits to using REST?

Clear Seperation

625. What are the RESTful characteristics?

Client-Server Stateless Cacheable Uniform Interface Layered System Code On Demand

459. What does AWS focus on?

Cloud Computing or services that take the need for certain infrastructure out of the way of programmers and host them on their websites

80. Comparable vs Comparator

Comparable is an interface that compares an object based on natural ordering (numbers and letters). It uses a convention of positive number for greater than the compared element, negative number for less than the compared element, and 0 for equal. Comparator is an interface that implements Comparable and implements its compareTo method for custom ordering. Comparator allows you to implement your own rules.

35. RunTime vs CompileTime

Compile time is when the JVM compiles your java source code into bytecode. Runtime is when your compiled Java code is run when a user uses your application.

20. What are the types of Polymorphism?

Compile time polymorphism (static) Runtime polymorphism (dynamic)

370. What are components?

Components are the most basic building block of a UI in an angular application. Everything in angular components and the application is represented as a tree of these components.

221. What is a composite Primary Key?

Composite Key or Composite Primary key, refers to cases where more than one column is used to specify the primary key of a table. In such cases, all foreign keys will also need to include all the columns in the composite key. Note that the columns that make up a composite key can be of different data types.

588. How do I integrate Spring and Hibernate?

Connect to a data source (Optional) Make ApplicationContext.xml and define the datasource and information Create a POJO to represent the table in the Java program Create and Define a hibernate mapping file between a <hibernate-mapping> file to define and explain the persistence in a class Create a DAO or template to persist the POJO class Define where the mapping for the bean is in the ApplicationContextFile and hibernate properties Create a new class to call methods of the DAO class

225. Connection vs DriverManager.

Connection is the actual connection to the database where you can load statements DriverManager loads the driver needed to connect to the database (if configured correctly) and generates a connection object on the java side.

204. Which are the main interfaces of JDBC?

Connection: Provides a way to access the session established with a DB server Statement: Provides a way to execute SQL statements and return the results using the ResultSet Objects Prepared statement: Callable statement Result Set

169. What is Consistency?

Consistency - ensures that any transaction will bring the database from one valid state to another. (does not protect for correctness of transaction)

579. Types of Dependency Injection

Constructor-Based Setter-Based: When the container calls setter methods on your beans after it has invoked either a no-arg constructor, or a no-arg static factory method to instantiate that bean

301. What are the different content types?

Content types is also known MIME (Multipurpose Internet Mail Extension) Type Commonly used content types: text/html text/plain application/jar application/pdf images/jpeg images/png images/gif audio/mp3 video/mp4

435. What is CD?

Continuous Deployment The next step after integration that is aimed at minimizing lead time. Lead time is the time elapsed from a new push and that new code being used by live users in production Continuous deployment is achieved by automating the various steps leading up to deployment so that after integration is successfully complete the live application is updated with the new code. Continuous Delivery Very similar to continuous deployment with the exception that continuous delivery doesn't mean that the code is deployed just that it is deployable at a given time.

645. How do you build a RESTful Web Service using Maven?

Create a Maven Project with a war Add Spring Dependencies: Spring-core, Spring-web,Spring-webmvc, jackson-databind Implement REST resources: RestController: Marks a class as a resource and combines the @Controller and @ResponseBody annotations RequestMapping: Defines the URL of the resource in addition to the method type: GET, POST, etc RequestParam: annotation represents a specific request parameter RequestBody: this annotation represents the body of the request Configure the REST API Deploy the REST API

146. What is DCL? What are the keywords?

DCL stands for data control language, and its the sub language that's used to grant and revoke users of their rights and permissions to a database The keywords are GRANT and REVOKE

145. What is DML? What are the keywords?

DML stands for Data Manipulation Language, The commands of SQL that are used to insert data into the database, modify the data of the database and to delete data from the database are collectively called as DML. You can insert rows into the table, update rows and delete rows The keywords are INSERT, UPDATE, DELETE

317. What are the different types of XML parsing?

DOM parser SAX parser JDOM parser StAX parser XPath parser DOM4J parser

147. What is DQL? What are the keywords?

DQL stands for Data Query Language. The commands of SQL that are used to retrieve data from the database are collectively called as DQL. So all Select statements comes under DQL. The keyword with DQL is SELECT DQL is sometimes included in DML

232. What is a view?

DUPLICATE

207. Aggregate Function.

DUPLICATE SEE 182.

287. What is AJAX?

DUPLICATE SEE 259

121. Where are Strings stored in memory?

Depends on how they're declared, the JVM however does create a special section of memory in the heap for strings called the string pool. Using new creates a string object that's stored in the heap with other objects When a string is declared using string literals it is added to the string pool.

373. What is a directive?

Directives allow you to attach behavior to elements in the DOM. Directives are identified with the @Directive decorator. Directives must be present in the declarations field of your NgModule for it to be usable by another directive, component, or application.

417. What is a Directive? Which are the types? Examples

Directives allow you to attach behavior to elements in the DOM. Directives must be specified in the NgModule in the declarations array. There are three types of Directives Component Structural Attribute

321. What is a Dispatcher?

Dispatcher is part of the Front Controller Design Pattern It is responsible for view management and navigation

246. What is DOM?

Document Object Model Represents the html page structure as nodes and objects. That way programming languages can connect to the page. Root node is the window object

653. What is DTD?

Document Type Definition Defines the structure and the legal elements and attributes of an XML document

447. What are the different package management systems in UNIX?

Dpkg Entropy Flatpack Apt-get (no longer apt-get i think just apt) Homebrew yum

313. What are the types of XSL?

Duplicate of 312

171. What is Durability?

Durability - ensures that once a transaction has been committed, it will remain committed even in the event of power loss, crashes, or errors. Once a sequence of statements execute the results need to be stored permanently in non-volatile memory to defend against these faults.

472. EBS vs S3?

EBS is not a standalone service and must be used in conjunction with EC2 or other associated services meant to store data in volumes of a predefined size like a hard drive on a physical machine. S3 is standalone and typically meant for large storage functions like database backups although that's not its sole purpose.

627. What does it mean to be Stateless?

Each request from client to server must contain all of the information necessary to understand the request, and cannot take advantage of any stored context on the server. Session state is therefore kept entirely on the client.

465. What is EBS?

Elastic Block Store A traditional 'block' storage resource that is provisioned to other AWS services.

583. How do I enable/configure annotations?

Enabled by <context:annotation-config> Configured in the you can move the bean configuration into the component class itself by using annotations on the relevant class, method, or field declaration

23. What is Encapsulation?

Encapsulation is a technique to control an object's accessibility to its states. You can achieve this control using access modifiers. The access modifiers are public, protected, default, and private. Public refers to global accessibility. Protected refers to accessibility within the package and its subclasses. Default refers to accessibility within the package and not its subclasses. Private refers to accessibility within that class only. These access modifiers are used for info hiding or data hiding.

124. Can I catch an error? Does it make sense?

Errors do inherit from the throwable class so yes they can be caught However it doesn't make sense to catch them because there's not typically anything you can do to handle an error.

443. What are the Maven Goals?

Experience with maven is limited, from what i understand, goals are: Processes that that maven binds to certain lifecycle phases that execute when calling a specific phase and in a specific order. Goals can be defined and added

22. How do you achieve Inheritance?

Extend class

685. SOAP exception handling.

Fault code will be communicated in the SOAP-ENV:Fault tag. A fault string describing the exception is communicated in the same tag. A fault actor provides information about where in the message path the fault occurred.

39. What is File I/O?

File Input Output Java uses the concept of a stream to speed I/O. streams can be used to read/write from and to the console, files, data, and more.

86. Which is the fastest File IO available and why?

File Input Reader - reads your file line by line

93. What is the final keyword used for?

Final is a non-access modifier Final used on objects and variables makes them immutable Final used on a class makes it uninheritable. Final used on methods make them non overridable.

328. Forward() vs Include()

Forward() - forwards a request from a servlet to another resource Include() - includes the contents of a resource into the response

571. What is Spring?

Framework created to address the complexity of enterprise level application Includes an Inversion of Control container Involves layered architecture that users can select which aspects of Spring to use Components/Modules - Test, Core Container, Web, Data Access and Integration, AOP

271. What are the types of functions?

Function declaration - create a function but don't assign it to a variable Function expression - create a function and assign it to a variable

187. Functions vs Stored Procedures

Functions are defined and must return some value. Functions can only have input parameters with predefined output parameters. Stored Procedures are just a series of steps that are taken at a given point. Procedures can have input and output parameters.

423. HTTP calls in Angular.

Get Post Put Delete

497. What is HBM?

HBM stands for Hibernate Mapping. This tells hibernate how to map a given object to a relational database.

551. How to create queries?

HQL - OOP way of writing query Hibernate Query Language Uses bean names and properties Native SQL Criteria - programmatically create queries

490. What is HQL?

HQL is Hibernate Query Language. HQL is hibernates version of SQL. It is made to act more like OOP.

576. What is the Spring Container?

IOC Container Application Context Bean Factory

103. What is the IS-A rule?

IS-A refers to an inheritance association, Objects that inherit from other objects have an is-a relationship with those objects (a lab IS-A dog).

96. How do you go about starting a thread?

If implementing Runnable, invoke the method run If extending Thread, invoke the method start, which will invoke the method run

244. What are the different forms of CSS?

If this question is referring to the different ways in which css can be applied to an html document then: External - In a separate file that's linked. Internal - At the top of the document in style tags. Inline - as an attribute on the elements themselves.

582. How do I create a bean in the container?

If you are using XML-based configuration metadata, you can specify the type (or class) of object that is to be instantiated using the 'class' attribute of the <bean/> element. You can declare beans using the @Bean annotation in a configuration class. Or you can mark the class with one of the annotations from the org.springframework.stereotype package and leave the rest to component scanning.

419. How do I inject an object into another object?

If you were to inject a service into one of your components for example: Create a service (services are annotated with the injectable decorator) Add the service class to the providers array of NgModule Declare the service in the constructor of the component it's to be injected into Angular takes care of the rest, you reference it with this.serviceName.method/property.

323. What is the deployment descriptor?

In J2EE, a deployment descriptor describes how a component should be deployed. An example of a "deployment descriptor" is the web.xml.

378. What is Data Binding?

In angular 4 data binding is how data manipulation in an angular component or web-page is done. One-way data binding When properties of the model get updated so does the UI or the opposite not both. Can flow two ways from html doc to scripts or from scripts to html doc. Doc to scripts When the user changes a field on an webpage you can capture it quickly and easily with a one way data binding done in angular 4 with [ name ]. Scripts to doc When you want to display the value of a variable in your script in the html doc but but the values is calculated or volatile meaning there's no guarantee you know what it is you could use a one way data binding from the script to the page. This is done using interpolation represented by {{ varname }}. Two-way data binding Means that when properties of the model get updated, so does the UI and the reverse is true. This is done in angular 4 using the ngModel directive.

369. What is a module?

In angular a module is a mechanism to group components, directives, pipes, and services that are related, in such a way that can be combined with other modules to create an application. Modules can be easily imported and exported for use.

120. What is a short circuit operator?

In java there are two (&& and ||) && will evaluate to false if the first half of the expression evaluates to false || will evaluate to true if the first half of the expression evaluates to true

283. Are JS objects mutable or immutable?

In javascript, only objects and arrays are mutable. Primitives are immutable.

418. What is Routing?

In the context of a web application routing is the process of directing users through the different pages of the application and controlling where the user goes when clicking a link or a button.

LinkedHashSet

Inherits from HashSet.

422. Syntax for all types of data binding.

Interpolation - {{ value }} Property - [property] = 'expression' Attribute - [attr.attrName]='expression' Class - [class.className]='expression' Style - [style.styleProperty]='expression'

197. Inner Join vs Intersect

Intersect is used to retrieve the common records from both the left and the right query of the intersect operator. Intersect does all columns where as inner join does only the specified columns. Despite this the intersect operator returns almost the same result as an inner join a lot of the time.

100. How do you insert elements in a Map?

Invoke the maps put method.

82. How do I start a thread implementing Runnable?

Invoke the run method to start a thread implementing Runnable. The Runnable object needs to be passed through the thread constructor and have invoke start.

111. How do I start a Thread extending the Thread class

Invoke the start method

396. What is linting?

Is a practice to encourage best practices when writing code. An automated process that checks practices like spacing, naming, variable declaration, etc.

2. Why would you choose Java?

Large developer community Huge amount of documentation Great exception handling Good for enterprise level applications A lot of environments support java Forwards compatible

503. Lazy Fetching vs Eager Fetching

Lazy Fetching - waits until the data is required and then gets it if not used it can lead to a LazyInstatiantionException Eager Fetching - gets the data as soon as it can get the information from the database

729. How to deploy your app on PCF

Manifest Name Instances RandomRoute Memory Path (of your jar) Cf push Pushes your jar to pcf to deploy your application 730. Annotations to know -> Web Service - @WebService - @WebMethod -> Restful Web Service - @Path - @GET - @PUT - @POST - @DELETE -> Spring - @Autowired - @Bean - @Transactional - @Scope -> Stereotypes - @Service - @Repository - @Component - @Controller - MVC -> @RestController -> @RequestMapping -> @PathVariable -> @RequestsParam -> @ModelAttribute -> @SessionAttributes -> @RequestBody/@ResponseBody - AOP -> @Aspect -> @Around - Data -> @Entity -> @Table -> @Column -> @ID -> @OneToOne/@OneToMany/@ManyToOne/@ManyToMany -> @GeneratedValue - Security -> @PreAuthorize - Boot -> @EnableAutoConfiguration -> @SpringBootApplication -> Eureka - @EnableEurekaServer - @EnableEurekaClient -> Zuul - @EnableZuulProxy -@EnableDiscoveryClient

109. What is a Map?

Map is an object that maps keys to values. Maps cannot have duplicate keys Each key can only map to at most one value. Put - places an object into the map Get - returns an object from the map at a specific key Remove - removes the mapping from the key if present. containsKey - returns a boolean for whether or not a map holds a specific key value. containsValue - returns true if the map contains a value else false Size - returns the number of key-value mappings in the map. Empty - returns true if the map is empty Clear - removes all key value pairs from the map

585. @Autowired.

Marks a constructor, field, setter method or config method as to be autowired by Spring's dependency injection facilities. Only one constructor (at max) of any given bean class may carry this annotation, indicating the constructor to autowire when used as a Spring bean. Such a constructor does not have to be public.

595. What is @RequestMapping?

Marks a method as an endpoint to which a client can connect, where you can specify the request type it will handle and the path of the endpoint.

441. What is Maven?

Maven is a project management tool that comes with a dependency manager to import plugins and external dependencies to your project. Comes with a cli that can be used to test, build, and package your application.

309. What is XMLNS?

Means XML namespaces Is used to avoid element name conflicts

19. How do you achieve Polymorphism?

Method overriding Method overloading

723. How do the microservices register with the Discovery?

Microservices register themselves Registry Heartbeats - lets Discovery know it's still alive

722. What is a microservice?

Modular in design, can be running many instances Not monolithic Easy to scale Self-contained Well-defined scope - perform one action Part of a larger architecture Micro doesn't refer to its size, but of its part in the larger whole

647. How do you expose a Web Service?

Module CXF Servlet in our deployment descriptor (web.xml) Create our Server Endpoint Interface (SEI) }Include our Create our Service implementing Bean (SIB) }@WebService annotation Register our endpoint in our beans.xml

57. What is Multithreading? How do you do it?

Multithreading is when your threads are running concurrently and handling different tasks. With one processor, multithreading isn't possible, but with multiple processors, it is. The OS divides processing time among different applications and also among each thread within an application.

374. What is a Structural Directive?

Must be annotated with @Directive decorator. Structural directives are responsible for HTML layout. They shape or reshape the DOM's structure by adding, removing, or manipulating elements. Structural directives is how Angular does DOM manipulation. Actions of Structural directives also affect children elements. Examples are: NgIf NgFor NgSwitch

397. What is NPM?

NPM is the Node Package Manager Npm is a package manager used for web technologies Npm has a software registry with a bunch of packages (modules) Used to share reusable code and keep it up to date. Npm could refer to a couple of things, the website, the registry, or the client CLI.

491. What is Native SQL?

Native SQL is a way of running regular SQL queries in Hibernate.

1. What is Java?

OOP programming language Common programming language Compiled programming language where the source code needs to be compiled into bytecode before it can run

485. What does ORM consists of?

ORM consists of taking an existing bean, and mapping it to a relational database. To start, you would annotate the class with the @Entity annotation. You would then annotate the class @Table and give it a table name. As for the variables of the class, you must annotate the ID with @Id, and all of the other variables with @column.

484. What is ORM?

ORM stands for Object Relational Mapping. It is a way to relate a programs beans to a relational database. You can you annotations like @Id to specify that a particular variable is the ID for that table and so on.

379. What are the types of Data Bindings?

One-way Two-way

726. Different services

PAAS - upload application Heroku PCF OpenShift IAAS - setup environment AWS Azure SAAS - use the application Gmail Google Docs

633. What the HTTP Methods? What CRUD operations do they correspond to?

POST (Create) GET (Read) PUT (Update) Patch(Update) DELETE (Delete)

589. How do I make Spring handle transactions for me? Configuration?

Programmatic transaction management : This means that you have to manage the transaction with the help of programming. That gives you extreme flexibility, but it is difficult to maintain. Declarative transaction management: This means you separate transaction management from the business code. You only use annotations or XML based configuration to manage the transactions.

92. What is the difference between protected and default?

Protected locks access of resources to class and subclass instances of the class in question. Default locks the access of resources to the package.

353. Method signature doGet.

Protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException.

351. Service method in HttpServlet.

Protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException.

573. Bean Scopes.

Prototype - Properties changed in one instance won't affect other instances of that bean Singleton - Properties changed on a global level (default) Request - (web service) scope of a single HTTP request Session - (web service) within a session GlobalSession - (web service) lifecycle of a global HTTP session

10. What are the Access Modifiers?

Public - globally accessible Protected - accessible within the package and its subclasses Default - accessible only within the package Private - accessible only within that class

350. What is the service method signature on GenericServlet?

Public abstract void service(ServletRequest req, ServletResponse res) throws ServletException, java.io.IOException.

172. What are the different Isolation Levels? What anomalies does each allow?

Read Uncommitted - allows all anomalies. Read Committed - prevents dirty reads, suffers non-repeatable and phantom reads. Repeatable Read - prevents non-repeatable reads, suffers phantom reads. Serialized - prevents all anomalies including phantom reads

306. What is Well-Formed XML?

Refers to an XML document that satisfies certain rules specified by the W3C documents with correct syntax A Well-Formed XML requires that: Content be defined Content be delimited with beginning and end tag Content be properly nested There can be only one root tag

438. What is IT Infrastructure?

Refers to the composite hardware, software, network resources, and services required for the existence, operation, and management of an enterprise IT environment

61. What are Reflections?

Reflections refers to the accessing and manipulating a class at runtime. When the JVM compiles code, it will leave the names of methods and data and leave executable machine code, so that another method can take an object and read its method names and data names. Reflection is generally used in frameworks to operate on objects without having those objects be of any particular class.

473. What is RDS?

Relational Database Service Makes it easy to set up, operate, and scale a relational database like postgreSQL, mySQL, or OracleSQL.

611. Transaction propagation strategies

Required - supports a transaction and creates a new one if it none exists Mandatory - supports a current transaction and will throw an exception if none exists Never - executes non-transactionally and throws an exception if a transaction exists Supported - Supports a current transaction if one exists but will execute non-transactionally if none exists. Not Supported - executes non-transactionally and suspends the current transaction if none exists Requires New - Will suspend the current transaction and create a new transaction if it exists Nested - it's nested, part of the transaction

640. What is Postman?

Rest client used to test a Web Service can be used to send all HTTP request to specific url's

728. Components of CF

Router - direct incoming traffic to cloud controller Authentication - OAuth Cloud Controller NSync - receives message from cloud controller when you scale the app BBS - handles desired LRP == actual LRP; creates/destroys instances to keep those numbers equal; stores disposable data (application status, heartbeats) Cell Replication - gives the actual LRP Storage: Blob Store - stores binary files Diego Cell - manages lifecycle of containers (Garden containers) and processes running in them; also reports their status to the BBS; makes logs and metrics to Loggregator Service Broker - look up services Consul - long term information; ip address Loggregator - streams application logs to the developer Metrics Collector

389. What is Routing? How do we implement it?

Routing is the ability to send users from one page in an application to another page in the application and back.

235. All sections of the SELECT statement.

SELECT (contents) FROM (table) WHERE (constraints);

142. What is SQL?

SQL stands for Structured Query Language and it's a programming language used to communicate with the data stored in relational database management system. SQL has sublanguages that are used specifically to either create/alter/drop tables, add/update/delete row entries in those tables, control what data you're retrieving from the tables, control user permissions, and handle transactions.

55. STACK vs VECTOR?

STACK is a data structure which extends Vector, and it stores objects in a last-in-first-out matter. The last object to be added will be the first one to be removed. VECTOR is a resizable data structure. It allows duplicate elements to be inserted and preserves insertion order. VECTOR is synchronized, so it is thread safe. Vector implements RandomAccess interface, so its retrieval methods are very fast. A vector increases in size by double. The Vector includes five methods that allows it to be treated like a stack. Those five methods are push, pop, peek, empty, and search.

149. What tools do you need to run an SQL Statement?

Schema to write your query in??

383. What is a Service?

Services are angular's way of fetching/storing data. Angular has services so that components don't have to both fetch data and display/present it in the view. Reduces code bloat. Increases modularity. Can use the same service in multiple components or applications.

612. What is SOAP?

Simple object access protocol. Communication protocol to communicate via Internet. Only supports XML messaging protocol via HTTP. Can be both stateless and stateful. Built-in error handling. XML document contains envelope, header, body, and fault.

380. How do you make a class a component?

Simply specify that a class is a component by annotating it with the @Component decorator.

463. What is SaaS?

Software as a service is a software distribution model in which a third-party provider hosts applications and makes them available to customers over the internet. (google docs, gmail, etc.)

720. What is Spring Data?

Spring module for abstracting database connection and querying operations using Hibernate as its ORM (Object Relational Mapper)

457. What is IAM?

Stands for Identity and Access Management Enables users to manage access to AWS services and resources securely You can use IAM to create and manage user groups with permissions for AWS resources.

316. What is JAXB?

Stands for Java Architecture for XML Binding It is used to convert Java Object to XML and XML to Java Objects

188. What is OLAP?

Stands for Online Analytical Processing. A data analytics tool.

189. What is OLTP?

Stands for Online Transaction Processing. A transactional tool.

300. What is TCP/IP?

Stands for Transmission Control Protocol/Internet Protocol. It is a communication protocol used to interconnect network devices on the internet. It is a suite that encompasses a number of different protocols for different purpose and needs

315. What is XPath?

Stands for XML Path Language Used to navigate through elements and attributes in an XML document Core component of XSLT Defines part of the XML document Provides powerful "path expressions" Used to select node or list of nodes from an XML document Provides library of standard functions for manipulating string, numbers, etc.

5. State vs Behavior

States are properties of an object Behaviors are actions that an object can take

279. What are the data types in JavaScript? (6)

String Number Boolean Undefined Arrays Objects Symbols Function

652. What is an XML Schema?

Structure and set up of an XML document

143. What are subtypes/sublanguages of SQL?

Sublanguages are a group of commands in SQL used to work with specific parts of a database table. DDL, DML, DQL, DCL TCL

95. What is synchronization?

Synchronization is the process of making resources thread-safe Done using the 'synchronize' keyword Makes object only accessible by one thread

148. What is TCL? What are the keywords?

TCL stands for Transaction control language. Transaction Control Language commands are used to manage transactions in database. These are used to manage the changes made by DML-statements. The keywords are COMMIT, ROLLBACK, SAVEPOINT

152. What are Tables?

Tables are data objects under a schema object and it holds columns that contain your data entries.

696. What happens if you don't have a gateway? Can you have microservices without this?

Technically, yes, you can have a microservice architecture without a gateway, but because your gateway helps you to route to each of your microservice instance, without the gateway, the client would have to know the url of each microservice instance, but even then, it wouldn't know if the microservice instance was active because there's no gateway to query the discovery service, which receives heartbeats from the microservice. The client can't query the discovery service. The discovery service doesn't receive requests from the client, only heartbeats from the microservices and sends a list of the active ones to the gateway.

133. Annotations.

Test - Denotes a method as a test. Before - Runs before every test. BeforeClass - Runs once before the class is run. After - Runs after each test. AfterClass - Runs once after the tests are done. Ignore - ignore a test temporarily

492. What is the Criteria API? How does it differ from HQL?

The Criteria API is one main interfaces of Hibernate. It allows for programmatic querying of the database. They use restrictions and projections. Restrictions act like a where clause, while projections act like aggregate functions. Criteria API differs from HQL in that it is fully programmatic. HQL is still structured like SQL. It just understands OOP principles.. 493. What is so special about Hibernate 4.0+? Has to do with sessionfactory creation

498. What do you need to include in the HBM?

The HBM must have a class name, and what entity it relates to in the database. It must have at least an ID specified, and how to generate the ID.

495. What do you need to include in the hibernate.cfg.xml file?

The Hibernate config file must have all the details to setup the sessionfactory. These details are the connection info, dialect, and driver. It must also have all mappings in a mapping tag. Driver Dialect Username Password URL Link to mapping file

411. Explain the Http module.

The Http Module is deprecated and it's now common practice to use the HttpClient Module instead. The HttpClient module is used to send Http requests and receive responses. It's set up by injecting it into the component meant to use it, done by placing a private variable in the constructor. You can reference the http variable to send http request and return observables and promises.

486. What are the ORM Levels?

The ORM levels are: Pure Relational Mapping - stored procedure Light ORM Mapping - like JDBC Medium ORM Mapping Full ORM Mapping alike Hibernate

262. What is DOM Manipulation?

The altering of the DOM while the application is running. You can use this to add remove and change the way elements are laid out and how they look on the page.

404. When you start the angular application, what is the entry point of it, where does it start? (bootstrap).

The base application bootstraps with AppComponent defined as the only endpoint by default. This can be changed by adding a new component to the bootstrap array in NgModule.

338. Explain the communication between the Client and the Server in a JEE application.

The client communicates with the business tier running on the Java EE server either directly or, as in the case of a client running in a browser, by going through web pages or servlets running in the web tier

602. Aspect.

The encapsulation of a cross cutting concern The combination of Pointcut and Advice

76. Which method does the garbage collector call?

The garbage collector calls finalize() before destroying the object which is eligible for garbage collection. This method shouldn't be overridden. You can trick the garbage collector by letting it think the object was already collected. User threads will be frozen. The finalize method was also deprecated in Java 9.

33. What is the Garbage Collector?

The garbage collector is a long running thread (daemon thread) which gets rid of objects that no longer hold a reference in the heap to free up space.

216. What is the Serializable Isolation level?

The highest of the transaction isolation levels. Protects against all of the read anomalies Dirty read Non-repeatable read Phantom read

578. Inversion of Control.

The idea that parts of the architecture you set up yourself, you pass on to some other entity to handle for you. Don't worry about the implementation, focus on the business logic. Spring uses dependency injection, which implements inversion of control.

341. Init, Service and Destroy, how many times do they execute?

The init and destroy method is called once The service method is called for every requests the servlet receives

391. What is the lifecycle of a component?

The lifecycle of a component is managed by angular itself, creation, rendering, data-bound properties, and it has hooks for you to allow you to respond to these events The most used is probably ngOnInit which is generated for every component when using ng g c.

385. What is Interpolation?

The populating of a placeholder with values from a string or variable to be viewed by the user. Done with {{ varname }}

119. What is constructor chaining?

The process of calling one constructor from within another constructor

368. What is minification?

The process of removing unnecessary or redundant data without affecting how the resources is processed by the browser. Example would be removing of white space, comments, unused code, shorter variable and function names and so on. Used to compress source code files for deployment.

210. What is the Read Committed Isolation level?

The second isolation level. Protects from dirty reads.

132. What does a Unit refer to?

The smallest testable subset of an application. In most languages that's functions or methods.

460. What is Cloud Computing?

The use of remote servers through a network to do computation tasks like program execution, storage, management and processing of data

452. What are the important parts of SCRUM?

There are three main components: The product owner: the company The scrum master: project manager The scrum team: the developers The master defines sprints and features with difficulty points The team takes features and develops them Progress is tracked throughout the development process with standups and tests.

445. What are the phases in the Build Lifecycle?

There's a bunch: Validate Compile Test Package Integration-test Verify Install Deploy

227. What is a theta join?

Theta joins allow for arbitrary comparison relationships (>, <, >=, <=, =). Theta joins using an equality operator are called equijoin. A natural join is a equijoin on attributes that have the same name in each relationship.

340. Where do init, service and destroy come from in the hierarchy?

They come from the Servlet interface

431. Generics in TypeScript.

They exist Similar to how java does it

180. What is 3NF?

Third Normal Form, the next step form 2NF. To be in 3NF the relation must first be in 2NF. To be in 3NF the relation's attributes must not be determined by non-prime attributes "All columns must depend on the whole key if they aren't part of the key." Remove Transitive Dependencies or anything that can be defined by another column

253. What tag would you use to create list?

Three different lists Ordered list Ol li Unordered list Ul li Description list Dl Dt Dd

475. What are the EC2 instance types?

Three main types T2 M5 M4 Each have small medium and larger subdivisions.

32. Throw vs Throws

Throw - method body to invoke an exception; act of throwing an exception explicitly; throw is followed by an instance variable Throws - method signature; used to declare an exception; throws is followed by exception class names

123. What's the parent of all exceptions?

Throwable Exception RuntimeException Error

639. What tools should I use to test a Web Service?

Tools we've used: PostMan, SoapUI

694. What exception will get thrown if you try to run the client (single microservice) before the server (eureka)?

Transport Exception

428. Access Modifiers in TypeScript?

Typescript has two Public and private

614. What is RESTful?

Uniform interface Client-Server independence Stateless Cacheable Layered System Code on demand(optional)

223. UNION vs UNION ALL.

Union all command is equal to the union command, except that union all selects all values. The difference between them is that union all will not eliminate duplicate rows, instead it pulls all rows from all tables fitting the query specifics and combines them into a table.

196. What are the different types of Indexes?

Unique - Guarantees unique values for the column(s) included in the index. Covering - includes all of the columns that are used in a particular query(set of queries), allowing the database to use only the index and not actually have to look at table data to retrieve the results. Clustered - this is a way in which the actual data is ordered on the disk, which means if a query uses the clustered index for looking up the values, it does not have to take the additional step of looking up the actual table row for any data not included in the index.

649. What is UDDI?

Universal Description Discovery and Integration An XML-based registry for businesses worldwide to list themselves on the internet

255. What does attribute "required" do?

Used on input to specify that it must be filled out for the form to submit.

642. What is XML Namespace?

Used to provide unique named elements and attributes in an XML document Keeps name conflicts when combining elements from two XML documents

41. What are the Data Structures in Java?

Various structures of holding data Array - one block of memory; constant access time ArrayList - dynamically resizable; object Vector - dynamically resizable; object LinkedList - uses nodes Set - unique values; sortable Queue - FIFO Tree - binary search tree Map - key value; not sortable Deque - accessible from both ends Stack - LIFO

635. What is WSDL?

Web Services Description Language

224. Can I do a subquery in a DELETE statement?

Yes Can also go in a where clause. Or a from clause.

664. How do you create a RESTful Web Service?

a. Explain all the steps to expose and consume.

662. Protocol stack.

a. Transport Protocol. b. Messaging Protocol. c. Description Protocol. d. Discovery Protocol.

626. What does it mean to be Layered?

allows an architecture to be composed of hierarchical layers by constraining component behavior such that each component cannot "see" beyond the immediate layer with which they are interacting.

137. Different types of assert methods.

assertTrue assertEquals assertFalse assertSame assertNotSame assertNull assertNotNull assertArrayEquals assertThat

702. What is Docker?

computer program that performs operating-system-level virtualization also known as containerization Containerization is the OS-level virtualization method used to deploy and run distributed applications without launching an entire virtual machine (VM) for each app

705. Docker commands.

docker swarm init --advertise-address [ ip ](in our case ip of our ec2) docker swarm leave docker swarm join docker node ls docker node ps docker service create docker service ls docker service ps [ service id ] docker service rm [ service id ] docker service scale

706. Image vs Instance.

image is an inert, immutable, file that's essentially a snapshot of a container A lightweight, stand-alone, executable package of a piece of software that includes everything needed to run it.

127. How do I insert elements in a map?

put