Inheritance and Aggregation in Java Language

There are two fundamental mechanisms for building new classes from existing ones: inheritance and aggregation. It makes sense to inherit from an existing class Vehicle to define a class Car, since a car is a vehicle. The class Vehicle has several parts; therefore, it makes sense to define a composite object of class Vehicle that [...]

Java Instance and Static Members

Each object created will have its own copies of the fields defined in its class. The fields of an object are called instance variables. The values of the instance variables in an object comprise its state. Two distinct objects can have the same state, if their instance variables have the same values. The methods of [...]

Objects of Java

Class Instantiation

The process of creating objects from a class is called instantiation. An object is an instance of a class. The object is constructed using the class as a blueprint and is a concrete instance of the abstraction that the class represents. An object must be created before it can be used in a program. [...]

Basics of Java Programming

Introduction

Before embarking on the road to Java programmer certification, it is important to understand the basic terminology and concepts in object-oriented programming (OOP). In this chapter, the emphasis is on providing an introduction rather than an exhaustive coverage. In-depth coverage of the concepts follows in due course in subsequent chapters of the book.
Java supports the [...]