Java: Empty while loop

Question

I\'m making a program with while loops that execute in this manner:

1. Main thread enters a while loop.
2. Nothing happens in the while loop.
3. Threa

Answer 1

Busy waits are very expensive. I'd do it this way:

Object LOCK = new Object(); // just something to lock on

synchronized (LOCK) {
    while (path != null) {
        try { LOCK.wait(); }
        catch (InterruptedException e) {
            // treat interrupt as exit request
            break;
        }
    }
}

Then when you set path to null, just call

synchronized (LOCK) {
    LOCK.notifyAll();
}

(You can just synchronize on this if both pieces of code are in the same object.)