Thread

current thread get a lock on the object when it executes a synchronized method.the lock will be released when the thread executes wait() method or it returns the method.
my doubt is:
whether the lock will be released when the thread executes yeild() or other methods that cause the thread to change from the running state???

second doubt:
when one thread calls sleep() method, will thread shedular allow another thread to execute???

http://java.sun.com/j2se/1.3/docs/api/index.html
See the above documentation.
The sleep does not loose ownership of any monitors.
A call to yield causes the currently executing thread to move to the Ready state if the scheduler is willing to run any other thread in place of the yielding thread. I wrote a small piece of code and put "yield" inside of synchronized code. It never gave up the monitor. At the same time I had another piece of synchronized code waiting for the object. It never ran.

boone in java2 exam guide in page 300 stating that
"the lock can be released when a synchronized method executes wait(),yeild(),or other methods that cause the threda to change from running state."
is this statement wrong???

When the method called wait() or yield() thread goes to Ready_to_run state (or waiting state after wait() call)that is it is not in the running state. So it has to release the lock.

hi,
some one can clear my doubt with a piece of code.

hi,
some one help me!!!
to clear my doubt with a piece of code.

Hello Jeena,
From what I could gather from Khalid Mughal, the yield() method is used to relinquish processor resources (CPU). I do not think it will relase the lock on the monitor. This is more to do with processor resource sharing rather than object locks I believe.
So if a thread is waiting for an object lock and a second thread has the object lock, executing the yield() method in the second thread should not relase the object lock.
Somebody please correct me if wrong.
Thanks