Introduction of Java

James Gosling and Sun Microsystems

Initially named asOak

Characterstics of java

• Java is simple
• Java is object-oriented
• Java is distributed
• Java is interpreted
• Java is robust
• Java is secure
• Java is architecture-neutral
• Java is portable
• Java’s performance
• Java is multithreaded
• Java is dynamic

Simple :

Java is Easy to write and more readable and eye catching.

Java has a concise, cohesive set of features that makes it easy to learn and use.

Most of the concepts are drew from C++ thus making Java learning simpler.

Secure :

Java program cannot harm other system thus making it secure.

Java provides a secure means of creating Internet applications.

Java provides secure way to access web applications.

Portable :

Java programs can execute in any environment for which there is a Java run-time system.(JVM)

Java programs can be run on any platform (Linux,Window,Mac)

Java programs can be transferred over world wide web (e.g applets)

Robust :

Java encourages error-free programming by being strictly typed and performing run-time checks.

Multithreaded :

Java provides integrated support for multithreaded programming.

Architecture-neutral :

Java is not tied to a specific machine or operating system architecture.

Machine Independent i.e Java is independent of hardware .

Interpreted :

Java supports cross-platform code through the use of Java bytecode.

Bytecode can be interpreted on any platform by JVM.

High performance :

Bytecodes are highly optimized.

JVM can executed them much faster .

Distributed :

Java was designed with the distributed environment.

Java can be transmit,run over internet.

Dynamic :

Java programs carry with them substantial amounts of run-time type information that is used to verify and resolve accesses to objects at run time.

JDK Versions

• JDK 1.02 (1995)
• JDK 1.1 (1996)
• Java 2 SDK v 1.2 (a.k.a JDK 1.2, 1998)
• Java 2 SDK v 1.3 (a.k.a JDK 1.3, 2000)
• Java 2 SDK v 1.4 (a.k.a JDK 1.4, 2002)

Example programe

//This application program prints Welcome

//to Java!

 package chapter1;

 public class Welcome {

 public static void main(String[] args) {

 System.out.println("Welcome to Java!");

}

}