What is Java?

#1 Java Basics

What is Java?

Java is a high-level, general-purpose, object-oriented, and secure programming

language developed by James Gosling at Sun Microsystems, Inc. in 1991. It is

formally known as OAK. In 1995, Sun Microsystem changed the name to Java.

In 2009, Sun Microsystem takeover by Oracle Corporation.

Editions of Java

Each edition of Java has different capabilities. There are three editions of Java:

Java Standard Editions (JSE):It is used to create programs for a desktop

computer.

Java Enterprise Edition (JEE):It is used to create large programs that run on

the server and manages heavy traffic and complex transactions.

Java Micro Edition (JME):It is used to develop applications for small devices

such as set-top boxes, phone, and appliances.

Types of Java Applications

There are four types of Java applications that can be created using Java

programming:

Standalone Applications:Java standalone applications uses GUI components

such as AWT, Swing, and JavaFX. These components contain buttons, list,

menu, scroll panel, etc. It is also known as desktop alienations.

Enterprise Applications:An application which is distributed in nature is called

enterprise applications.

Web Applications:An applications that run on the server is called web

applications. We use JSP, Servlet, Spring, and Hibernate technologies for

creating web applications.

Mobile Applications:Java ME is a cross-platform to develop mobile

applications which run across smartphones. Java is a platform for App

Development in Android.

Java Platform

Java Platform is a collection of programs. It helps to develop and run a program

written in the Java programming language. Java Platform includes an execution

engine, a compiler and set of libraries. Java is a platform-independent

language.Features of Java

Simple:Java is a simple language because its syntax is simple, clean, and easy

to understand. Complex and ambiguous concepts of C++ are either eliminated

or re-implemented in Java. For example, pointer and operator overloading are

not used in Java.

Object-Oriented:In Java, everything is in the form of the object. It means it

has some data and behavior. A program must have at least one class and

object.

Robust:Java makes an effort to check error at run time and compile time. It

uses a strong memory management system called garbage collector. Exception

handling and garbage collection features make it strong.

Secure:Java is a secure programming language because it has no explicit

pointer and programs runs in the virtual machine. Java contains a security

manager that defines the access of Java classes.

Platform-Independent:Java provides a guarantee that code writes once and

run anywhere. This byte code is platform-independent and can be run on any

machine.

Portable:Java Byte code can be carried to any platform. No implementation-

dependent features. Everything related to storage is predefined, for example,

the size of primitive data types.

High Performance:Java is an interpreted language. Java enables high

performance with the use of the Just-In-Time compiler.

Distributed:Java also has networking facilities. It is designed for the

distributed environment of the internet because it supports TCP/IP protocol. It

can run over the internet. EJB and RMI are used to create a distributed system.

Multi-threaded:Java also supports multi-threading. It means to handle more

than one job a time.

OOPs (Object Oriented Programming System)

Object-oriented programming is a way of solving a complex problem by

breaking them into a small sub-problem. An object is a real-world entity. It is

easier to develop a program by using an object. In OOPs, we create programs

using class and object in a structured manner.

Class:A class is a template or blueprint or prototype that defines data

members and methods of an object. An object is the instance of the class. We

can define a class by using the class keyword.

Object:An object is a real-world entity that can be identified distinctly. For

example, a desk, a circle can be considered as objects. An object has a unique

behavior, identity, and state. Data fields with their current values represent the

state of an object (also known as its properties or attributes).

Abstraction:An abstraction is a method of hiding irrelevant information from

the user. For example, the driver only knows how to drive a car; there is no

need to know how does the car run. We can make a class abstract by using the

keyword abstract. In Java, we use abstract class and interface to achieve

abstraction.

Encapsulation:An encapsulation is the process of binding data and functions

into a single unit. A class is an example of encapsulation. In Java, Java bean is a

fully encapsulated class.

Inheritance:Inheritance is the mechanism in which one class acquire all the

features of another class. We can achieve inheritance by using the extends

keyword. It facilitates the reusability of the code.

Polymorphism:The polymorphism is the ability to appear in many forms. In

other words, single action in different ways. For example, a boy in the

classroom behaves like a student, in house behaves like a son. There are two

types of polymorphism: run time polymorphism and compile-time

polymorphism.