Environmental setting :
operating system : window media center
environment setting of the class path  :

Command-line testing
 
GUI : using swing with eclipse

import javax.swing.*;
public class test {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String str = "Hello Wrold";
//System.out.println("Hello Wrold");
JOptionPane.showMessageDialog(null, str) ;
}
}