How to wait for a thread that spawns it's own thread?

Question

I\'m trying to test a method that does it\'s work in a separate thread, simplified it\'s like this:

public void methodToTest()
{
    Thread thread = new Thre         


        

Answer 1

Since your threads seems to be performing different operations, you can use CountDownLatch to solve your problem.

Declare a CountDownLatch in main thread and pass this latch object to other threads. use await() in main thread and decrement latch in other threads.

In Main thread: ( first thread)

CountDownLatch latch = new CountDownLatch(2);
/* Create Second thread and pass the latch. Pass the same latch from second 
   thread to third thread when you are creating third thread */
try {
    latch.await();
} catch (InterruptedException e) {
    e.printStackTrace();
}

Pass this latch to second and third threads and use countdown in these threads

In second and third threads,

try {
    // add your business logic i.e. run() method implementation
    latch.countDown();
} catch (InterruptedException e) {
    e.printStackTrace();
}

Have a look this article for better understanding.

ExecutorService invokeAll() API is other preferable solution.