public class Concurrence { 
    public static void main(String[] args) { 
      WareHouse wareHouse = new WareHouse(); 
      Producer producer = new Producer(wareHouse); 
      Consumer consumer = new Consumer(wareHouse); 
   
      new Thread(producer).start(); 
      new Thread(consumer).start(); 
    } 
  } 
   
  class WareHouse { 
    private static final int STORE_SIZE = 10; 
    private String[] storeProducts = new String[STORE_SIZE]; 
    private int index = 0; 
   
    public void pushProduct(String product) { 
      synchronized (this) { 
        while (index == STORE_SIZE) { 
          try { 
            this.wait(); 
          } catch (InterruptedException e) { 
            e.printStackTrace(); 
          } 
        } 
   
        storeProducts[index++] = product; 
        this.notify(); 
   
        System.out.println("生產(chǎn)了: " + product + " , 目前倉庫里共: " + index 
            + " 個貨物"); 
      } 
    } 
   
    public synchronized String getProduct() { 
      synchronized (this) { 
        while (index == 0) { 
          try { 
            this.wait(); 
          } catch (InterruptedException e) { 
            e.printStackTrace(); 
          } 
        } 
   
        String product = storeProducts[index - 1]; 
        index--; 
        System.out.println("消費了: " + product + ", 目前倉庫里共: " + index 
            + " 個貨物"); 
        this.notify(); 
        return product; 
      } 
    } 
  } 
   
  class Producer implements Runnable { 
    WareHouse wareHouse; 
   
    public Producer(WareHouse wh) { 
      this.wareHouse = wh; 
    } 
   
    @Override 
    public void run() { 
      for (int i = 0; i < 40; i++) { 
        String product = "product" + i; 
        this.wareHouse.pushProduct(product); 
      } 
    } 
  } 
   
  class Consumer implements Runnable { 
    WareHouse wareHouse; 
   
    public Consumer(WareHouse wh) { 
      this.wareHouse = wh; 
    } 
   
    @Override 
    public void run() { 
      for (int i = 0; i < 40; i++) { 
        this.wareHouse.getProduct(); 
      } 
    } 
  }