java 多线程问题

Question

package yang.test;import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;public class Exercise22 { public static void main(String[] args) {
Thread coop1 = new Thread(new Coop1());
coop1.start();
Thread coop2 = new Thread(new Coop2(coop1));
coop2.start();

// Runnable coop1 = new Coop1(), 
//              coop2 = new Coop2(coop1); 
//     ExecutorService exec = Executors.newCachedThreadPool(); 
//     exec.execute(coop1); 
//     exec.execute(coop2); 
//     Thread.yield(); 
//     exec.shutdown(); }
}class Coop1 implements Runnable {
public Coop1(){
System.out.println("Coop1 constructed!");
}
@Override
public void run() {
System.out.println("Coop1 going into wait...");
synchronized(this){
try{
wait();
}catch(InterruptedException e){
System.out.println("Stoped by InterruptedException.");
}
System.out.println("Coop1 is running to the exit.");
}
}
}class Coop2 implements Runnable {
Runnable otherTask;
public Coop2(Runnable otherTask){
this.otherTask = otherTask;
System.out.println("Coop2 constructed.");
}
@Override
public void run() {
System.out.println("Coop2 pause 5 seconds.");
try {
TimeUnit.SECONDS.sleep(2);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Notify other task now...");
synchronized(otherTask){
otherTask.notifyAll();
}
}
}
当我注释之后Coop1的线程就无法执行完毕，注释start方法启用线程，改用execute之后却好好的，这是为什么？这两种方式有什么区别？请高手指点！

Answer 1

Thread coop1 = new Thread(new Coop1());  传得是new Coop1() 对象 他被wait() 没人唤醒他
coop1.start();
Thread coop2 = new Thread(new Coop2(coop1)); 你的otherTask.notifyAll(); 的对象锁otherTask 和前面new Coop1() 不是同一个 唤醒不了前面的等待

Answer 2

Runnable coop1 = new Coop1(), 
// coop2 = new Coop2(coop1); 
// ExecutorService exec = Executors.newCachedThreadPool(); 
// exec.execute(coop1); 
// exec.execute(coop2); 
// Thread.yield(); 
// exec.shutdown();
共用 同一个对象 coop1 当然可以唤醒前面 一个等待是 new Coop1()对象 唤醒的是new Thread(new Coop1())对象 不是同一个唤醒不了

Answer 3

楼上说的很好了，这样改一下就行了Runnable c1 = new Coop1();
Thread coop1 = new Thread(c1);
coop1.start();
Thread coop2 = new Thread(new Coop2(c1));
coop2.start();
锁的不是同一个对象