Hi friend

Green threads are simulated threads within the VM and were used prior to going to a native OS threading model in 1.2 and beyond. Green threads may have had an advantage on Linux at one point (since you don't have to spawn a process for each native thread), but VM technology has advanced significantly since version 1.1 and any benefit green threads had in the past is erased by the performance increases over the years.

This is simple program of thread

public class ThreadExample extends Thread {
public ThreadExample(String str) {
super(str);
}
public void run() {
for (int i = 0; i < 10; i++) {
System.out.println(i + " " + getName());
try {
sleep((int)(Math.random() * 1000));
} catch(InterruptedException e){
System.out.println(e);
}
}
System.out.println("Complete! " + getName());
}
public static void main (String[] args) {
new ThreadExample("Roseindia").start();
new ThreadExample("javajazzup").start();
new ThreadExample("newstrackindia").start();
System.out.println("Welcome to Roseindia");
}
}

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Read for more information

http://www.roseindia.net/java/