Question

I have scenario: I want to wait, until something is false. Usually takes likes 20 seconds or so.

while(foo) {
    try {
        Thread.sleep(5000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

Or just go like this?

while(foo) {

}

Answer 1

Busy waiting for 20 seconds is not a good idea – and sleeping for 5 seconds means you might miss the signal by 5 seconds. Can’t you use a different way, such as a CountdownLatch:

CountDownLatch latch = new CountDownLatch(1);

//code that triggers the signal
latch.countDown();

//code that waits for the signal
try {
    latch.await();
} catch (InterruptedException e) {
    //handle interruption
}