How can we create the `notify ()` method in an object?

Question

I was asked this question in an interview.

How you can create your own notify() method ?

I said that this is a method nativeand cannot be overridden.

But she was not happy with the answer.

Can someone explain?

Answer 1

I assume that the interviewer wanted to implement a Java version of something equivalent to a waiting / notification mechanism, without using Object.wait () and Object.notify () directly.

For example, any of the following high-level synchronization mechanisms can be used to simulate wait / notify:

• Implementing BlockingQueue
• SynchronousQueue
• CountDownLatch
• CyclicBarrier
• Futures

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, SynchronousQueue:

public class WaitNotify {
  private final Object ITEM = new Object(); 
  private final SynchronousQueue<Object> q = new SynchronousQueue<Object>();

  public void myNotify() {
    q.offer(ITEM);
  }

  public void myWait() throws InterruptedException {
    q.take();    
  }
}

Answer 2

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