what all ways a Thread can leave a lock on Object

[Vivek Nidhi]

hello there
Suppose a Threads enter a sychronised block, the lock is release when the Thread dies in it and also when the thread comes out of the sychronised block.
ANY OTHER CASES THE LOCK CAN BE RELEASED
Vivek Nidhi

[David Hadiprijanto]

Another way the lock can be release if the thread invoke a wait method of the same object whose lock is the same.
The code below if run as expected will result in :
Thread A - waiting to be notified.
Main Thread: About to notify a.
Thread A - has been notified.
It demonstrates that A releases the lock (of itself) when it invokes the wait() method and allow the Main Thread to enter the synchronized(a) block.

  
class A implements Runnable {
  public void run() {
    synchronized(this) {
      System.out.println(Thread.currentThread().getName() +
        " - waiting to be notified.");
      try { wait(); } catch (InterruptedException ie) {}
      System.out.println(Thread.currentThread().getName() +
        " - has been notified.");
    }
  }
}
public class TestWaitReleaseLock {
  public static void main(String[] args) {
    A a = new A();
    Thread t = new Thread(a, "Thread A");
    t.start();
    // give threat t to run
    try { Thread.sleep(1000); } catch (InterruptedException ie) {}
    synchronized(a) {
      System.out.println("Main Thread: About to notify a.");
      a.notify();
    }
  }
}

P.S. : There is a little guarantee in Thread behavior, hence, I am undermining the sleep() method in the code above for the sake of demonstration only.

[Vivek Nidhi]

Thanks Boss
regs
Vivek Nidhi