Object-Oriented Programming Concepts Quiz

Object-Oriented Programming (OOP)

• OOP is a programming methodology that defines objects to accomplish a given task through their behaviors and interactions.

Object

• An object is a fundamental concept in OOP with characteristics or attributes.
• Objects have a state defined by the values of their attributes.
• Objects can perform actions known as behaviors, which are defined by methods.

Class

• A class is a blueprint for defining objects.
• Objects of the same kind have the same data type and belong to the same class.
• The data type of an object is the name of its class.

Inheritance

• Inheritance is a way of organizing classes that allows objects of a class to inherit properties from objects in another class.
• The extends keyword is used to apply inheritance.

Interface

• An interface is a program component containing the heading for a number of public methods.
• It is used by another class through the implements keyword.

Package

• A package is a collection of related classes and interfaces grouped together into a folder.
• Classes within a package can be used by any program or class with an import statement.

Methods

• A parameter is the list of variables in a method declaration.
• An argument is the actual value passed when a method is invoked.
• The void keyword denotes that a method does not return a value.
• A method is a collection of statements grouped together to perform an operation.

Variables

• Instance variables are variables declared outside the method, constructor, or any block, associated with an instance of a class.
• The this keyword represents the object's name receiving the method call within a method definition.
• Local variables are variables declared within a method definition, visible only to the methods in which they are declared.

Principles of OOP

• Information hiding is the mechanism for restricting access to some of the object's components to improve clarity, maintainability, and reusability.
• Encapsulation is the process of combining data and actions into a single item, grouping instance variables and methods into a class while hiding implementation details.

UML Class Diagram

• A UML class diagram describes the structure of a class by displaying the class name, variables, and methods.

Object Behavior

• Behavior refers to the actions that an object can take, defined by a piece of Java code called a method.
• An accessor is a public method that returns data from a private instance variable.
• A mutator is a public method that changes the data stored in one or more private instance variables.
• The equals method is used for comparison instead of the == operator when dealing with objects.