Mastering OOP Fundamentals: Objects, Classes, and Java Terms

Core Concepts of Object-Oriented Programming (OOP)

Object Characteristics: State and Behavior

Objects in real life possess two primary characteristics: state and behavior.

• State: Defined by a set of parameters that define and distinguish an object from others of the same type.
• Behavior: Allows distinguishing objects of different types (e.g., a dog object behaves differently than a cat object).

Class Structure and Components

A class is a template or prototype that defines a particular object type. A class defines the attributes and methods that an object will possess.

Defining Object Components

Attributes or Member Variables

The parameters or variables that define the state of an object.

Methods or Member Functions

Actions that objects can perform.

Accessing Attributes

Attributes of an object are accessed using Methods.

Object Communication

Objects communicate with each other via messages.

Methods in OOP

Actions that can be performed with objects.

Key OOP Mechanisms

Method Overloading

When a class has methods with the same name but differing either in the number or type of parameters, this is called Method Overloading.

Encapsulation (Information Hiding)

An object normally has a public part used by other objects for interaction, and a hidden part to conceal implementation details. This concept is known as Encapsulation.

Inheritance

A fundamental OOP mechanism defined as the transmission of characteristics (methods and attributes) from parent classes to child classes is Inheritance.

Java Specific Concepts

Java Servlets

A Java Servlet is a Java application that runs on a server, handling requests (pleas) from a client (typically a web browser), and lacks a graphical interface.

Java Applets

Java Applets are dynamic and interactive programs that run within a web page loaded by a web browser.

Garbage Collection

The Java procedure that automatically locates and removes memory that is no longer needed. This process is performed without the need for explicit calls: Garbage Collector.

Variable Initialization in the Main Class

The correct approach is to declare variables in the class scope and assign values or initialize them within the constructor.