现在看到了多线程，有个例子，如下。CountingThread 类就是个计数的类。ThreadTest创建了3个线程 
public class ThreadTest  
{ 
    public static void main(String args[]) 
    { 
        System.out.println("Thread started."); 
        CountingThread thread1=new CountingThread(); 
        thread1.start(); 
        CountingThread thread2=new CountingThread(); 
        thread2.start(); 
        CountingThread thread3=new CountingThread(); 
        thread3.start(); 
    } 
} 
 
 
public class CountingThread extends Thread 
{ 
    public void run() 
    { 
         System.out.println("Thread started:"+[color=FF0000]this[/color]); 
         for(int i=0;i<9;i++) 
         { 
             System.out.print("i="+(i+1)+"\t"); 
         } 
         System.out.println("Thread stopped:"+this); 
    } 
} 
 
现在想问个问题 ，被我标记为彩色部分的那个+this是什么意思啊。 
 
输出结果是： 
 
Thread started. 
Thread started:Thread[Thread-1,5,main] 
Thread started:Thread[Thread-0,5,main] 
Thread started:Thread[Thread-2,5,main] 
i=1    i=2    i=3    i=4    i=5    i=6    i=7    i=8    i=9    Thread stopped:Thread[Thread-2,5,main] 
i=1    i=2    i=3    i=4    i=5    i=6    i=7    i=8    i=9    Thread stopped:Thread[Thread-0,5,main] 
i=1    i=2    i=3    i=4    i=5    i=6    i=7    i=8    i=9    Thread stopped:Thread[Thread-1,5,main]