What is Thread.Join() in threading ?

There are two versions of Thread.Join :-
√ Thread.join().
√ Thread.join(Integer) this returns a Boolean value.
The Thread.Join method is useful for determining if a thread has completed before starting another task. The Join method waits a specified amount of time for a thread to end. If the thread ends before the time-out, Join returns true; otherwise it returns False. Once you call Join, the calling procedure stops and waits for the thread to signal that it is done.
Example you have "Thread1" and "Thread2" and while executing 'Thread1" you call" Thread2.Join()".So Thread1" will wait until "Thread2" has completed its execution and the again invoke "Thread1".
Thread.Join(Integer) ensures that threads do not wait for a long time. If it exceeds a specific time which is provided in integer the waiting thread will start.