Objects: Instances of Classes - AP Computer Science A

An instance of a class. Objects are concrete realizations of classes with specific data values.

Constructor. Constructors set initial values for object instance variables.

Current object instance. Allows access to current object's fields and methods within class.

Constructor. Constructors execute automatically during object creation process.

null. Uninitialized object references automatically default to null value.

Hiding internal state and requiring all interaction through methods. Protects data integrity by controlling access through methods.

Instantiation. The act of creating a specific object from a class blueprint.

public. Provides unrestricted access across all classes and packages.

Default constructor is invoked. Creates object with default field values when no parameters given.

equals(). Compares object content rather than reference addresses.

interface. Defines contracts that implementing classes must fulfill.

final. Prevents inheritance by making class non-extendable.

A variable defined in a class for which each instantiated object has its own value. Each object maintains its own copy of these variables.

ClassName.variableName. Static variables belong to class, accessed via class name.

this. References the specific object calling the method or constructor.

extends. Establishes parent-child relationship between classes for code reuse.

==. Tests reference equality, not object content comparison.

toString(). Provides readable text representation for debugging and display.

extends. Establishes parent-child relationship between classes for code reuse.

List. Ordered collections that maintain insertion order and duplicates.

Default constructor is invoked. Creates object with default field values when no parameters given.

Instance method. Non-static methods require object instance to be invoked.

this. References the specific object calling the method or constructor.

final. Makes variables immutable after initial assignment.

Ability of different classes to be treated as instances of the same class through inheritance. Enables single interface to represent different underlying types.

implements. Establishes contract between interface and implementing class.

Instantiation. The act of creating a specific object from a class blueprint.

final. Prevents inheritance by making class non-extendable.

A variable defined in a class for which each instantiated object has its own value. Each object maintains its own copy of these variables.