用JAVA实现多线程（生产者与消费者问题）

public class MultiThread {
 public static void main(String[] args) {
  ProductStack box = new ProductStack("box");
  Producer p1 = new Producer(box, "p1");
  Producer p2 = new Producer(box, "p2");
  Producer p3 = new Producer(box, "p3");
  Consumer c1 = new Consumer(box, "c1");
  Consumer c2 = new Consumer(box, "c2");
  //Consumer c3=new Consumer(box,"c3");
  //Consumer c4=new Consumer(box,"c4");
   //Consumer c5=new Consumer(box,"c5");
  p1.start();
  p2.start();
  p3.start();
  c1.start();
  c2.start();
    //c3.start();
     //c4.start();
    // c5.start();
 }
}
class Product {
 int id;
 public Product(int id) {
  this.id = id;
 }
 public String toSring() {
  return "Product" + id;
 }
}
class ProductStack {
 String name;
 static int point = 0;
 private Product[] p = new Product[10];
 public ProductStack(String name) {
  this.name = name;
 }
 public String getname() {
  return name;
 }
 public synchronized int getpoint() {
  return point;
 }
 public synchronized void push(Product a) {
  while (point >= p.length) {
   try {
    this.wait();
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
   this.notifyAll();
  }
  p[point] = a;
  // System.out.println(point);
  // System.out.println(p[point].toSring());
  point++;
  // yield();
 }
 private void yield() {
 }
 public synchronized Product pop() {
  while (point == 0) {
   try {