Java/Java Testing/C++

What is an array?

Array is a group of related data items that share a common name.For instance, we can define an array name salary to represent a set of salaries of a group of employees. Examples : salary[10]

What is the difference between an Array and a List?

The main difference between an array and a list is how they internally store the data. whereas Array is collection of homogeneous elements. List is collection of heterogeneous elements.

What is Software reliability?

Software reliability is defined as the probability of failure free operation of a computer program in a specified environment for a specified time.

What is acceptance testing?

Testing the system with the intent of confirming readiness of the product and customer acceptance. Also known as User Acceptance Testing.

What is the Collection interface?

The Collection interface provides support for the implementation of a mathematical bag - an unordered collection of objects that may contain duplicates.

What is the Collections API?

The Collections API is a set of classes and interfaces that support operations on collections of objects.

Why use the MySQL Database Server?

The MySQL Database Server is very fast, reliable, and easy to use. it is possible for anyone to use and modify the software. Anybody can download the MySQL software from the Internet and use it without paying anything.

What must a class do to implement an interface?

The class must provide all of the methods in the interface and identify the interface in its implements clause.

What is the default port for MySQL Server?

The default port is 3306.

What is meant by validation?

Validation ensures that functionality, as defined in requirements, is the intended behavior of the product; validation typically involves actual testing and takes place after verifications are completed.

What are variables?

Variables are user defined named entities of memory locations that can store data.

What are the common problems with software automation?

. Purchasing the license of tool (QTP, selenium, QC, LR) 2. Lack of skilled Tester to run the tool 3. Expectation that automated tests will find a lot of new defects 4. Maintenance of automated tests 5. Technical problems of tools

What is multiple inheritance?

A class can inherit properties from more than one class which is known as multiple inheritance.

What is a Class?

A class is a blueprint for an object

Define Constructors?

A constructor is a member method with the same name as its class. The constructor is invoked whenever an object of its associated class is created.It is called constructor because it constructs the values of data members of the class.

What is fault?

A fault is a condition that causes a system to fail in performing its required function.

What is JAVA

A high-level programming language developed by Sun Microsystems. Java was originally called OAK, and was designed for handheld devices and set-top boxes. Oak was unsuccessful so in 1995 Sun changed the name to Java and modified the language to take advantage of the burgeoning World Wide Web.

What is a software review?

A software review can be defined as a filter for the software engineering process. The purpose of any review is to discover errors in the analysis, design, and coding, testing and implementation phases of the software development cycle. The other purpose of a review is to see whether procedures are applied uniformly and in a manageable manner.

What is the difference between static and non-static variables?

A static variable is associated with the class as a whole rather than with specific instances of a class. Non-static variables take on unique values with each object instance.

What are different types of access modifiers?

Access specifiers are keywords that determine the type of access to the member a class. Public Protected Private Default

What is Black box testing?

Black box testing is a test case design method that focuses on the functional requirements of the software. It is otherwise called as functional testing.

What is the difference between an instance variable and a static variable?

Class variables are called static variables. There is only one occurrence of a class variable per JVM per class loader.When a class is loaded the class variables are initialized. Instance variables are non-static and there is one occurrence of an instance variable in each class instance.Also known as a member variable or a field.

what are class variables

Class variables are global to a class and belong to the entire set of objects that class creates. Only one memory location is created for each variable

What are the advantages of inheritance?

Code reusability Saves time in program development.

What is the difference between constructors and normal methods?

Constructors must have the same name as the class and can not return a value. They are only called once while regular methods could be called many times and it can return a value or can be void.

What is the default access specifier?

Default

Use of each function in jquery?

Each function is used to iterate each and every element of an object. It is used to loop DOM elements, arrays and the object properties.

Basic Selectors in jquery

Element ID CSS Name Tag Name DOM hierarchy

What is the difference between error and an exception?

Exception means When a method encounters an abnormal condition (an exception condition) that it can't handle itself, it may throw an exception. ssError mens system doesn't handle.For example:Overflow,Out of memory

What is failure?

Failure is the inability of the software to perform a required function to its specification.

What is incremental testing?

Incremental testing is partial testing of an incomplete product. The goal of incremental testing is to provide an early feedback to software developers.

Define inheritance?

Inheritance is the process by which objects of one class acquire properties of objects of another class. It allows the extension and reuse of existing code without having to rewrite the code from scratch.

What is this pointer?

It is a pointer that points to the current object. This can be used to access the members of the current object with the help of the arrow operator.

What is singleton?

It is one of the design pattern. This falls in the creational pattern of the design pattern. There will be only one instance for that entire JVM. You can achieve this by having the private constructor in the class.

What is the LIKE?

LIKE pattern match, which succeeds only if the pattern matches the entire value.

What's MySQL?

MySQL the most popular Open Source SQL database management system, is developed, distributed, and supported by MySQL AB. MySQL AB is a commercial company, founded by the MySQL developers, that builds its business by providing services around the MySQL database management system.

What are the basic concepts of object oriented programming?

Object-oriented programming (OOP) is a programming language model organized around objects rather than "actions" and data rather than logic. Historically, a program has been viewed as a logical procedure that takes input data, processes it, and produces output data. The programming challenge was seen as how to write the logic, not how to define the data. Object-oriented programming takes the view that what we really care about are the objects we want to manipulate rather than the logic required to manipulate them.

What is the difference between method overriding and overloading?

Overriding is a method with the same name and arguments as in a parent, whereas overloading is the same method name but different arguments.

What are pass by reference and passby value?

Pass By Reference means the passing the address itself rather than passing the value. Passby Value means passing a copy of the value to be passed.

Define polymorphism?

Polymorphism simply means "many forms". In java polymorphism is acheived through method overloading and overriding. For example, say you have an Animal class and two sub classes called Lion and Cat class. All animals make a sound, so lets say there is a make sound method in all of these classes. When you call the make sound method from a lion object that is stored in an Animal reference, it would call the make sound method from the Lion Class. That is how you would explain polymorphism using overriding.

What is regression testing?

Regression testing is not a level of testing, but it is the retesting of software that occurs when changes are made to ensure that the new version of the software has retained the capabilities of the old version and that no new defects have been introduced due to the changes.

What are the types of reviews?

Reviews are one of two types : informal technical reviews and formal technical reviews. Informal Technical Review : An informal meeting and informal desk checking. Formal Technical Review : A formal software quality assurance activity through various approaches, such as structured walkthroughs, inspections, etc.

How do you get the current date in Mysql?

SELECT CURRENT_DATE();

What is the difference between static and dynamic testing?

Static testing : is performed using the software documentation. The code is not executing during static testing. Dynamic testing : requires the code to be in an executable state to perform the tests.

What is the main difference between a String and a StringBuffer class?

String is immutable : you can't modify a string object but can replace it by creating a new instance. Creating a new instance is rather expensive. StringBuffer is mutable : use StringBuffer or StringBuilder when you want to modify the contents. StringBuilder was added in Java 5 and it is identical in all respects to StringBuffer except that it is not synchronized,which makes it slightly faster at the cost of not being thread-safe.

What is the Java Virtual Machine (JVM)?

The Java Virtual Machine is software that can be ported onto various hardware-based platforms.

What is a list iterator?

The List and Set collections provide iterators, which are objects that allow going over all the elements of a collection in sequence. The java.util.Iterator interface provides for one-way traversal and java.util.ListIterator is an iterator for lists that allows the programmer to traverse the list in either direction (i.e. forward and or backward) and modify the list during iteration.

What is difference between Retesting and Regression testing?

The difference between Retesting and Regression testing are below: Retesting is done to verify defects fixes where as regression is perform to check if the defect fix have not impacted other functionality that was working fine before doing changes in the code. Retesting is planned testing based on the defect fixes listed where as regression is not be always specific to any defect fix. Also regression can be executed for some modules or all modules. Retesting concern with executing those test cases that are failed earlier whereas regression concern with executing test cases that was passed in earlier builds. Retesting has higher priority over regression, but in some case retesting and regression testing are carried out in parallel.

what is dot operator?

The dot operator(.) is used to access the instance variables and methods of class objects.It is also used to access classes and sub-packages from a package. Examples : Person1.age ---------> Reference to the variable age

What is the difference between an if statement and a switch statement?

The if statement is used to select among two alternatives. It uses a boolean expression to decide which alternative should be executed. The switch statement is used to select among multiple alternatives. It uses an int expression to determine which alternative should be executed.

What is type cast?

Type cast refers to the process of changing the data type of the value stored in a variable.

What is type casting?

Type casting means treating a variable of one type as though it is another type. Examples : int m = 5; byte n =i;

What is verification?

Verification ensures the product is designed to deliver all functionality to the customer; it typically involves reviews and meetings to evaluate documents, plans, code, requirements and specifications; this can be done with checklists, issues lists, walkthroughs and inspection meetings.

What are verification and validation and difference between these two?

Verification: process of evaluating steps which is followed up to development phase to determine whether they meet the specified requirements for that stage. Validation: process of evaluating product during or at the end of the development process to determine whether product meets specified requirements. Difference between Verification and Validation: Verification is Static Testing where as Validations is Dynamic Testing. Verification takes place before validation. Verification evaluates plans, documents, requirements and specifications, where as Validation evaluates product. Verification inputs are checklist, issues list, walkthroughs and inspection, where as in Validation testing of actual product. Verification output is set of documents, plans, specifications and requirement documents where as in Validation actual product is output.

What is the Java API?

What is the Java API? The Java API is a large collection of ready-made software components that provide many useful capabilities, such as graphical user interface (GUI) widgets.

What if the main method is declared as private?

When a method is declared as private, the program compiles properly but it will give runtime error Main method not "public„.

16. What is the basis for choosing the SDLC model for development of software?

When the requirements are very clearly know, documented and not subject to change then we can follow the waterfall model. Most of the companies follow the V mode for the development because this model includes both verification and validation activities and testing is involved in earlier phase. Iterative model can be used to build application where requirement changes after a period of times or application features or added on with smaller release. When the client is ready for the delivery of the product in parts or phases.

What is white box testing?

White box testing is a test case design method that uses the control structure of the procedural design to derive test cases. It is otherwise called as structural testing.

What are wrapped classes?

Wrapped classes are classes that allow primitive types to be accessed as objects.

What scenarios do we use jQuery

jQuery can be used in following scenarios: Apply CSS static or dynamic Calling functions on events Manipulation purpose Mainly for Animation effects

What is the base class of all classes?

java.lang.Object

What type of parameter passing does Java support?

pass by value

What are wrapper classes?

primitive data types may be converted into object types by using the wrapper classes contained in the java.lang package. Exampes : int, float, long, char, double

What are the types of Errors?

syntax, logic

What is an Object?

An instance of a class

what is a package?

A package is a namespace that organizes a set of related classes and interfaces.The classes contained in the packages of other programs can be easily reused.Packages, classes can be unique compared with classes in other packages.That is, two classes in two different packages can have the same name.

What is the difference between a while statement and a do while statement?

A while statement checks at the beginning of a loop to see whether the next loop iteration should occur. A do while statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do whilestatement will always execute the body of a loop at least once.

What is an abstract class?

Abstract class is a class which contain one or more abstract methods, which has to be implemented by sub classes. An abstract class can contain no abstract methods also i.e. abstract class may contain concrete methods. An abstract class CANNOT be instantiated.

agile methodology

Agile development model is also a type of Incremental model. Software is developed in incremental, rapid cycles. This results in small incremental releases with each release building on previous functionality. Each release is thoroughly tested to ensure software quality is maintained. It is used for time critical applications. Extreme Programming (XP) is currently one of the most well known agile development life cycle model.

What is the difference between an interface and an abstract class?

An abstract class may contain code in method bodies, which is not allowed in an interface. With abstract classes, you have to inherit your class from it and Java does not allow multiple inheritance. On the other hand, you can implement multiple interfaces in your class.

What is array of strings?

An array of strings is a two dimensional character array. The size of first index (rows) determines the number of strings and the size of second index () determines maximum length of each string.

Difference between build and release?

BUILD: is a number given to installable software that is given to testing team for testing by the development team. Build number assigned are incremental and sequential. RELEASE: is a number given to installable software that is handed over to customer by the developer or tester. The information of build, release and version are displayed in software help page. Using this build and release customer can let the customer team know which release version build thet are using.

What is the difference between black box and white box testing?

Black box testing is a testing strategy based solely on requirements and specifications. Black box testing requires no knowledge of internal paths, structures, or implementation of the software being tested. White box testing is a testing strategy based on internal paths, code structures, and implementation of the software being tested. White box testing generally requires detailed programming skills.

What is the difference between a break statement and a continue statement?

Break statement results in the termination of the statement to which it applies (switch, for, do, or while). A Continue statement is used to end the current loop iteration and return control to the loop statement.

How do you concatenate strings in MySQL?

CONCAT (string1, string2, string3)

What are the advantages of object oriented programming?

Class data type allows programs to organize as objects that contain both data and functions. Data hiding or Abstraction of data provides security to data, as unrelated member functions cannot access its data. Polymorphism promotes, reduces software complexity, as multiple definitions are permitted to an operator or function. Inheritance allows a class to be derived from an existing class, thus promoting reusability of code.

What is the difference between coupling and cohension?

Cohesion refers to what the class (or module) will do. Low cohesion would mean that the class does a great variety of actions and is not focused on what it should do. High cohesion would then mean that the class is focused on what it should be doing, i.e. only methods relating to the intention of the class As for coupling, it refers to how related are two classes / modules and how dependent they are on each other. Being low coupling would mean that changing something major in one class should not affect the other. High coupling would make your code difficult to make changes as well as to maintain it, as classes are coupled closely together, making a change could mean an entire system revamp. All good software design will go for high cohesion and low coupling.

What is an iterator?

Iterators are like pointers. They are used to access the elements of containers thus providing a link between algorithms and containers. Iterators are defined for specific containers and used as arguments to algorithms.

What is severity and priority of bug? Give some example.

Priority: concern with application from the business point of view. It answers: How quickly we need to fix the bug? Or How soon the bug should get fixed? Severity: concern with functionality of application. It deals with the impact of the bug on the application

Where and how can you use a private constructor?

Private constructor is used if you do not want other classes to instantiate the object and to prevent subclassing.The instantiation is done by a public static method (i.e. a static factory method) within the same class.

What are runtime exceptions?

Runtime exceptions are those exceptions that are thrown at runtime because of either wrong input data or because of wrong business logic etc. These are not checked by the compiler at compile time.

How do you return the a hundred books starting from 25th?

SELECT book_title FROM books LIMIT 25, 100;

How would you write a query to select all teams that won either 2, 4, 6 or 8 games?

SELECT team_name FROM teams WHERE team_won IN (2, 4, 6, 8).

How would you select all the users, whose phone number is null?

SELECT user_name FROM users WHERE ISNULL(user_phonenumber);

What is serialization?

Serialization is the process of converting a objects into a stream of bytes.

Difference in size and length of jquery

Size and length both returns the number of element in an object. But length is faster than the size because length is a property and size is a method

What is the difference between software engineering and system engineering?

Software Engineering is concerned with all aspects of computer based systems development including hardware, software and process engineering. System Engineering are involves in system specification architectural design intergration and deployment.

Define strings?

Strings represent a sequence of characters.The easiest way to represent a sequence of characters in java is by using a character array.

What is the difference between syntax and logical errors?

Syntax Error : A syntax error is a program statement that violates one or more rules of the language in which it is written. Logic Error : A logic error deals with incorrect data fields, out-of-range terms, and invalid combinations.

What are the advantages of waterfall model?

The waterfall model is a sequential design process, used in software development processes, in which progress is seen as flowing steadily downwards (like a waterfall) through the phases of conception, initiation, analysis, design, construction, testing, production/implementation and maintenance. The various advantages of the waterfall model include: It is a linear model. It is a segmental model. It is systematic and sequential. It is a simple one. It has proper documentation.

What is encapsulation?

The wrapping up of data and functions into a single unit (called class) is known as encapsulation. Encapsulation containing and hiding information about an object, such as internal data structures and code.

Why do threads block on I/O?

Threads block on i/o (that is enters the waiting state) so that other threads may execute while the i/o Operation is performed.

What is meant by unit testing?

Unit testing is the process of testing a particular complied program, i.e., a window, a report, an interface, etc. independently as a stand alone component/program. The types and degrees of unit tests can vary among modified and newly created programs. Unit testing is mostly performed by the programmers who are also responsible for the creation of the necessary unit test data.

What is a user defined exception?

User defined exceptions may be implemented by defining a new exception class by extending the Exception class.

What is variables and then types

Variables is an identifier that denotes a storage location used to store a data values.unlike constants that remain unchanged during the execution of a program, a variable may takes different values at different times during the execution of the program. Instance variables Class variables ***Class variables only have one copy that is shared by all the different objects of a class, whereas every object has it's own personal copy of an instance variable** Local variable Parameters

is jquery a JS or JSON library file?

jQuery is a library of JavaScript file and it consists of DOM, event effects and the Ajax functions. jQuery is said to be a single JavaScript file.

Why do we need jquery

jQuery is needed for the following list: Used to develop browser compatible web applications Improve the performance of an application Very fast and extensible UI related functions are written in minimal lines of codes

What is jQuery

jQuery is not a programming language but a well written JavaScript code. It is a JavaScript code, which do document traversing, event handling, Ajax interactions and Animations.

what is the use jqery.data methode?

jQuery.data methods is used to associate the data with the DOM nodes and the objects. This data method makes the jQuery code clear and concise.

What is the importance of static variable?

static variables are class level variables where all objects of the class refer to the same variable. If one object changes the value then the change gets reflected in all the objects.