Javaのプロデューサとコンシューマの例の詳細な説明

/*
 author by w3cschool.cc
 ProducerConsumerTest.java
 */
public class ProducerConsumerTest {
  public static void main(String[] args) {
   CubbyHole c = new CubbyHole();
   Producer p1 = new Producer(c, 1);
   Consumer c1 = new Consumer(c, 1);
   p1.start(); 
   c1.start();
  }
}
class CubbyHole {
  private int contents;
  private boolean available = false;
  public synchronized int get() {
   while (available == false) {
     try {
      wait();
     }
     catch (InterruptedException e) {
     }
   }
   available = false;
   notifyAll();
   return contents;
  }
  public synchronized void put(int value) {
   while (available == true) {
     try {
      wait();
     }
     catch (InterruptedException e) { 
     } 
   }
   contents = value;
   available = true;
   notifyAll();
  }
}
class Consumer extends Thread {
  private CubbyHole cubbyhole;
  private int number;
  public Consumer(CubbyHole c, int number) {
   cubbyhole = c;
   this.number = number;
  }
  public void run() {
   int value = 0;
     for (int i = 0; i < 10; i++) {
      value = cubbyhole.get();
      System.out.println("消费者 #" + this.number+ " got: " + value);
     }
  }
}
class Producer extends Thread {
  private CubbyHole cubbyhole;
  private int number;
  public Producer(CubbyHole c, int number) {
   cubbyhole = c;
   this.number = number;
  }
  public void run() {
   for (int i = 0; i < 10; i++) {
     cubbyhole.put(i);
     System.out.println("生产者 #" + this.number + " put: " + i);
     try {
      sleep((int)(Math.random() * 100));
     } catch (InterruptedException e) { }
   }
  }
}

消费者 #1 got: 0
生产者 #1 put: 0
生产者 #1 put: 1
消费者 #1 got: 1
生产者 #1 put: 2
消费者 #1 got: 2
生产者 #1 put: 3
消费者 #1 got: 3
生产者 #1 put: 4
消费者 #1 got: 4
生产者 #1 put: 5
消费者 #1 got: 5
生产者 #1 put: 6
消费者 #1 got: 6
生产者 #1 put: 7
消费者 #1 got: 7
生产者 #1 put: 8
消费者 #1 got: 8
生产者 #1 put: 9
消费者 #1 got: 9