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JavaJavaJava

•Java Virtual Machine (JVM)

•Java Application Program Interface (API)

HW

Kernel

API

Application Programs

JVM

Java APIs

Java Application

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Java APIsJava APIs

Client-Side applications

Server-Side applications

Client/Server applications

Internet (Web) applications

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JAVA CompilerJAVA Compiler

Java Compiler

Source

Code

Java

Byte Code

Readable

by

human

Executable

by

JVM

javac

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JAVA Virtual Machine JAVA Virtual Machine (JVM)(JVM)

JVM - JRE

Java

Byte Code

Executable

by

JVM

java

JVM for Windows

HP OS

Windows OS

Linux OS

Mac OS

JVM for Linux

JVM for HP

JVM for Mac

interpreter

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JavaJavaSoftware Development KitSoftware Development Kit

Download and install:

SDK 1.3 or higher

Commands in bin directory:

• javac – java compiler

• java - execution

• jar – java zip/tar

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Java Example:Java Example:Source CodeSource Code

//File: HelloWorld.javaimport java.io.*;

public class HelloWorld {

public static void main(String[] args){System.out.println("Hello World!"); } //End of main } //End of class

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Java Example:Java Example:Generate Byte CodeGenerate Byte Code

Source Code: HelloWorld.java

Set Path: set path=c:\sdk1.3\bin;%path%

Compile: javac HelloWorld.java

Byte code: HelloWorld.class

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Java Example:Java Example:Execute ByteCodeExecute ByteCode

java HelloWorld

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Java Example:Java Example:Windows98 - DOSWindows98 - DOS