IS 247 Vocab Chapter 9-13:

superclass

A class inherited from a subclass.

abstract data type (ADT)

A class is also known as an abstract data type.

immutable class

A class is immutable if it contains all private data fields and no mutator methods and no accessor methods that would return a reference to a mutable data field object.

subclass

A class that inherits from or extends a superclass.

static variable

A data member declared using the static modifier. A static variable is shared by all instances of that class. Static variables are used to communicate between different objects of the same class and to handle global states among these objects.

reference type

A data type that is a class or an interface.

declared type

A data type that is used to declare a reference variable. This type is called the declared type for the variable.

Unified Modeling Language (UML)

A graphical notation for describing classes and their relationships.

null value

A literal of a reference variable that does not reference any concrete object.

dynamic binding

A method may be defined in a superclass, but is overridden in a subclass. Which implementation of the method is used on a particular call will be determined dynamically by the JVM at runtime. This capability is known as dynamic binding.

abstract method

A method signature without implementation. Its implementation is provided by its subclasses. An abstract method is denoted with an abstract modifier and must be contained in an abstract class. In a nonabstract subclass extended from an abstract class, all abstract methods must be implemented, even if they are not used in the subclass.

behavior

A method that can be called by an object.

static method

A method that can be invoked without creating an instance of the class. To define static methods, put the modifier static in the method declaration.

getter (or accessor)

A method that returns the value from a data field.

setter (or mutator)

A method that sets a new value in a data field.

protected

A modifier for members of a class. A protected member of a class can be used in the class in which it is declared or any subclass derived from that class.

instance variable

A nonstatic data member of a class. An instance variable belongs to an instance of the class.

instance method

A nonstatic method in a class. Instance methods belong to instances and can only be invoked by them.

directory path

A path for a directory in the file system.

private constructor

A private constructor prevents constructing objects from the class.

throw exception

A program that detects an error can create an instance of an appropriate exception type and throw it. This is known as throwing an exception.

aggregation

A special form of association that represents an ownership relationship between two classes.

constructor

A special method for initializing objects when creating objects using the new operator. The constructor has exactly the same name as its defining class. Constructors can be overloaded, making it easier to construct objects with different initial data values.

stack

A stack is a data structure that holds objects in a last-in first-out fashion.

class abstraction

A technique in software development that hides detailed implementation. Class abstraction hides the implementation of the class from the client

reference variable

A variable of a class type.

attribute

A variable that stores a value for an object.

declare exception

All checked exceptions thrown by the method must be explicitly declared in the method declaration so that the caller of the method is informed of the exception.

absolute file name

An absolute filename (or full name) contains a filename with its complete path and drive letter.

marker interface

An empty interface that is used to signify that all the classes implementing the interface share certain properties.

class

An encapsulated collection of data and methods that operate on data. A class may be instantiated to create an object that is an instance of the class.

subinterface

An interface inherited from another interface.

interface

An interface is treated like a special class in Java. Each interface is compiled into a separate bytecode file, just like a regular class. You cannot create an instance for an interface. The structure of a Java interface is similar to that of an abstract class in that it can have data and methods. The data, however, must be constants, and the methods can have only declarations without implementation. Single inheritance is the Java restriction wherein a class can inherit from a single superclass. This restriction is eased by the use of an interface.

composition

An object consists of other objects. This is called composition.

anonymous object

An object created without being assigned to a reference variable.

instance

An object of a class.

immutable object

An object of immutable class.

Instance of

An operator that checks whether an object is an instance of a class.

dot operator (.)

An operator used to access members of an object. If the member is static, it can be accessed through the class name using the dot operator.

exception

An unexpected event indicating that a program has failed in some way. Exceptions are represented by exception objects in Java. Exceptions can be handled in a try-catch block.

object

Can be created from a class using the class's constructor.

class encapsulation

Combining of methods and data into a single data structure.

constructor chaining

Constructing an instance of a class invokes all the constructor chaining superclasses along the inheritance chain.

boxing

Converting a primitive value to a wrapper object is called boxing.

unboxing

Converting a primitive value to a wrapper object is called boxing. The reverse conversion is called unboxing.

casting objects

Converting an object of one object type into another object type. The contents of the object are not changed.

inheritance

Defining a new class by extending an existing class.

multiplicity

Each class involved in a relationship may specify a multiplicity. A multiplicity could be a number or an interval that specifies how many of the class's objects are involved in the relationship.

checked exception

Exceptions other than RuntimeException and Error.

default constructor

If a class does not define any constructors explicitly, a no-arg constructor with empty body is assumed. This is called a default constructor.

override

Implement the method in a subclass that is declared in a superclass.

unchecked exception

Instances of RuntimeException and Error.

multiple inheritance

Means that a class can extend multiple superclasses.

single inheritance

Means that a class can only extend one superclass.

client

Refers the program that uses a class. The program is known as a client of the class.

relative file name

Refers to a filename without the full path. Its path is implied in its working directory.

class's contract

Refers to the collection of methods and fields that are accessible from outside a class, together with the description of how these members are expected to behave.

exception propagation

Refers to the mechanism for catching exceptions in a chain of method calls. The exception is propagated through a chain of methods.

this keyword

Refers to the object itself.

class's variable

Refers to the variables defined in the class.

data field

Same as attribute.

property

Same as attribute.

action

Same as behavior.

method overriding

Same as overriding.

subtype

Same as subclass.

supertype

Same as superclass.

actual type

The actual type of the variable is the actual class for the object referenced by the variable.

type inference

The concrete type is no longer required in the constructor thanks to a feature called type inference.

instantiation

The process of creating an object of a class.

public class

The public visibility modifier is used for the class.

state

The state of an object is described by attributes of the object.

chained exception

Throw new exceptions along with the original exception.

data field encapsulation

To prevent direct modifications of properties through the object reference, you can declare the field private, using the private modifier. Data field encapsulation makes the class easy to maintain.

deep copy

When cloning an object, all its fields are cloned recursively.

shallow copy

When cloning an object, all its fields are copied.

abstract class

When you are designing classes, a superclass should contain common features that are shared by subclasses. Sometimes the superclass is so abstract that it cannot have any specific instances. These classes are called abstract classes and are declared using the abstract modifier. Abstract classes are like regular classes with data and methods, but you cannot create instances of abstract classes using the new operator.

has

a relationship- Composition models have a has-a relationship.

is

a relationship- Same as inheritance.

no

arg constructor- A constructor without arguments.

object

oriented programming (OOP)- An approach to programming that involves organizing objects and their behavior into classes of reusable components.

package

private (or package-access)- If public or private is not used, then by default the classes, methods, and data are accessible by any class in the same package. This is known as package-private or package-access.