Java는wait() 및 notifyAll() 방법으로 스레드 간 통신을 수행합니다.

package Threads;

import java.util.LinkedList;

/**
 * Created by Frank
 */
public class ProdCons {
 protected LinkedList<Object> list = new LinkedList<>();
 protected int max;
 protected boolean done = false;

 public static void main(String[] args) throws InterruptedException {
  ProdCons prodCons = new ProdCons(100, 3, 4);
  Thread.sleep(5 * 1000);
  synchronized (prodCons.list) {
   prodCons.done = true;
   try {
    prodCons.notifyAll();
   } catch (Exception ex) {
   }
  }
 }

 private ProdCons(int maxThreads, int nP, int nC) {
  this.max = maxThreads;
  for (int i = 0; i < nP; i++) {
   new Producer().start();
  }
  for (int i = 0; i < nC; i++) {
   new Consumer().start();
  }
 }

 class Producer extends Thread {
  public void run() {
   while (true) {
    Object justProduced = null;
    try {
     justProduced = getObj();
    } catch (InterruptedException e) {
     e.printStackTrace();
    }
    synchronized (list) {
     while (list.size() == max) {
      try {
       list.wait();
      } catch (InterruptedException e) {
       System.out.println("Producer INTERRUPTED");
      }
     }
     list.addFirst(justProduced);
     list.notifyAll();
     System.out.println("Produced 1;List size now " + list.size());
     if (done) {
      break;
     }
    }
   }
  }
 }

 class Consumer extends Thread {
  public void run() {
   while (true) {
    Object object = null;
    synchronized (list) {
     if (list.size() == 0) {
      try {
       list.wait();
      } catch (InterruptedException e) {
       System.out.println("Consumer INTERRUPTED");
      }
     }
     if (list.size() > 0) {
      object = list.removeLast();
     }
     list.notifyAll();
     System.out.println("List size now " + list.size());
     if (done) {
      break;
     }
    }
    if (null != object) {
     System.out.println("Consuming object " + object);
    }
   }
  }
 }

 private Object getObj() throws InterruptedException {
  Thread.sleep(1000);
  return new Object();
 }
}