java.lang.Object.wait() 導致當前線程等待，直到其他線程調用notify()方法或notifyAll()方法，此對象。換言之，此方法的行為就好像它簡單地執行調用wait(0)。

當前線程必須擁有該對象的監視器。該監視器並等待另一個線程的線程釋放所有權通知的線程在等待此對象的監視器上無論是通過調用notify方法或notifyAll方法喚醒。該線程要等到重新獲得對監視器的所有權後才能繼續執行。

這個方法隻能由一個線程是此對象監視器的所有者被調用。看到其中一個線程能夠成為監視器所有者的notify方法。

聲明

以下是java.lang.Object.wait()方法的聲明

public final void wait()

參數

• NA

返回值

這個方法冇有返回值。

異常

• IllegalMonitorStateException -- 如果當前線程不是對象監視器的擁有者。

• InterruptedException -- 如果另一個線程中斷了當前線程。當這種異常被拋出當前線程的中斷狀態被清除。

例子

下麵的例子顯示lang.Object.wait()方法的使用。

package com.yiibai;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class ObjectDemo extends Object {

   private List synchedList;

   public ObjectDemo() {
      // create a new synchronized list to be used
      synchedList = Collections.synchronizedList(new LinkedList());
   }

   // method used to remove an element from the list
   public String removeElement() throws InterruptedException {
      synchronized (synchedList) {

         // while the list is empty, wait
         while (synchedList.isEmpty()) {
            System.out.println("List is empty...");
            synchedList.wait();
            System.out.println("Waiting...");
         }
         String element = (String) synchedList.remove(0);

         return element;
      }
   }

   // method to add an element in the list
   public void addElement(String element) {
      System.out.println("Opening...");
      synchronized (synchedList) {

         // add an element and notify all that an element exists
         synchedList.add(element);
         System.out.println("New Element:'" + element + "'");

         synchedList.notifyAll();
         System.out.println("notifyAll called!");
      }
      System.out.println("Closing...");
   }

   public static void main(String[] args) {
      final ObjectDemo demo = new ObjectDemo();

      Runnable runA = new Runnable() {

         public void run() {
            try {
               String item = demo.removeElement();
               System.out.println("" + item);
            } catch (InterruptedException ix) {
               System.out.println("Interrupted Exception!");
            } catch (Exception x) {
               System.out.println("Exception thrown.");
            }
         }
      };

      Runnable runB = new Runnable() {

         // run adds an element in the list and starts the loop
         public void run() {
            demo.addElement("Hello!");
         }
      };

      try {
         Thread threadA1 = new Thread(runA, "A");
         threadA1.start();

         Thread.sleep(500);

         Thread threadA2 = new Thread(runA, "B");
         threadA2.start();

         Thread.sleep(500);

         Thread threadB = new Thread(runB, "C");
         threadB.start();

         Thread.sleep(1000);

         threadA1.interrupt();
         threadA2.interrupt();
      } catch (InterruptedException x) {
      }
   }
}

讓我們來編譯和運行上麵的程序，這將產生以下結果：

List is empty...
List is empty...
Opening...
New Element:'Hello!'
notifyAll called!
Closing...
Waiting...
Hello!
Waiting...
List is empty...
Interrupted Exception!