Introduction
Thread.join() is a method in Java that allows one thread to wait for the completion of another thread. It is commonly used to synchronize the execution of threads. However, it has been observed that Thread.join() does not always release the lock, which can lead to deadlocks and other issues. In this article, we will discuss the reasons why Thread.join() does not release the lock and how to avoid this issue. We will also look at some best practices for using Thread.join() in Java.
Solution
The thread.join() method does not release the lock. It is used to wait for a thread to finish its execution before continuing with the current thread. It is used to synchronize the execution of threads. When a thread calls join(), it will block the current thread until the thread it joins with completes its execution.
That’s because Thread.join() doesn’t release any locks. You’ve designed a perfectly working deadlock, where Thread-1 is waiting for Thread-2 to die having locked on Foo, and Thread-2 is waiting to lock on Foo.
(Technically speaking the current implementation does release locks, as it uses internally wait() while synchronized on Thread. However that’s an internal mechanism not related to user code)
solved Java – Thread.join( ) does not release the lock
Solved: Java – Thread.join() Does Not Release the Lock
Thread.join() is a method in Java that allows one thread to wait for the completion of another thread. It is commonly used to synchronize the execution of threads. However, it has been observed that Thread.join() does not release the lock, which can lead to deadlocks in certain situations.
A deadlock occurs when two or more threads are blocked forever, waiting for each other. This can happen when two threads are trying to acquire the same lock, and each thread is waiting for the other to release the lock. In this case, neither thread can proceed, and the application will hang.
The problem with Thread.join() is that it does not release the lock. This means that if two threads are trying to acquire the same lock, and one thread calls Thread.join() on the other, the lock will not be released until the thread that called Thread.join() is finished. This can lead to deadlocks in certain situations.
The solution to this problem is to use a different synchronization mechanism, such as a ReentrantLock. A ReentrantLock is a type of lock that can be acquired and released multiple times by the same thread. This means that if one thread calls Thread.join() on another thread, the lock will be released when the thread that called Thread.join() is finished.
In summary, Thread.join() does not release the lock, which can lead to deadlocks in certain situations. The solution is to use a different synchronization mechanism, such as a ReentrantLock.