THREADS :PLEASE HELP

[Raj Mehra]

Dear friends,
Can anyone explain to me why the following program, doesnot show any output.
Thnx in advance.

public class thread2  extends Thread{
static Object lock1=new Object();
static Object lock2=new Object();
static volatile int i1,i2,j1,j2,k1,k2;
  
public void run()
{
   while (true)
{
   doit();
   check();
}
}

void doit(){
synchronized(lock1)
{
i1++;
}
j1++;
synchronized(lock2)
{
k1++;k2++;
}
j2++;
synchronized(lock1)
{
i2++;
}
}
synchronized void check(){
if(i1==i2)
System.out.println("i");
if(j1!=j2)
System.out.println("j");
if(k1==k2)
System.out.println("k");
}
public static void main(String[] args)
{
  new thread2().start();
  new thread2().start();
}
}

[khudiram Barik]

This may be possible.
Since the doIT() is not synchronized both the thread can access the method concurrently. When the first one finishes the 1st synchronized block and goes for the statemnt j1++, the second one can enter into 1st synchronized block and so on, we can never predict the locks. Since the variables are volatile concurrent changes will effect both the threads and hence you may not have the System.out.println statements get executed.
Thanks.
khudi