How to lock with ReentrantLock?

Question

I would expect the following test to only print \"has been locked\" once. BUT it consequently prints the line.

public class LocKTest {
    @Test
    public void          


        

Answer 1

Considering Kayamans answer, you could implement your own Lock class:

public class Lock {

    private boolean isLocked = false;

    public synchronized void lock() throws InterruptedException {
        while(isLocked) {
            wait();
        }
        isLocked = true;
    }

    public synchronized void unlock() {
        isLocked = false;
        notify();
    }
}

Use it like this:

public class LocKTest {
    @Test
    public void testLock() {
        Lock lock = new Lock();
        while (true) {
            if (lock.lock()) {
                System.out.println("has been locked"); // prints only once
            }
        }
    }
}

Code example taken from this tutorial.