OnJava8-Examples/concurrency/Chopstick.java

// concurrency/Chopstick.java
// Chopsticks for dining philosophers.

public class Chopstick {
  private boolean taken = false;
  public synchronized
  void take() throws InterruptedException {
    while(taken)
      wait();
    taken = true;
  }
  public synchronized void drop() {
    taken = false;
    notifyAll();
  }
}