Question

Class ThreadTest extends Thread {
  public synchronized void run() {

  }

  public static void main(String args[])
  {
    Thread t1=new ThreadTest();
    Thread t2=new ThreadTest();
    t1.start();
    t2.start();
  }
}

I want to know in above scenario, how locks obtained and on which object?
Does above scenario valid?
As locks are obtained on a calling object in method synchronisation then in above scenario on which object lock will be obtained. One more question who(or which object) invokes the run method?

Thanks,
-Abhishek

Answer 1

t1 has the lock of the t1 instance.
t2 has the lock of the t2 instance.

But your example doesnt make much sense..

Maybe this example will help you:

public class Test extends Thread  {

private String name;

public Test(String name) {
    this.name = name;
}

public synchronized void run() {
    System.out.println(name);

    while(true) 
        { 
        // loop endless
        }
  }

  public static void main(String args[])
  {
    Thread t1= new Test("t1");
    Thread t2= new Test("t2");
    t1.start();
    t2.start();

  }

}

The output is:

t1
t2