JAva synchronized制御単一変数の自己増加

   /**    
    * @Title: ThreadTest3.java  
    * @Package com.lss.wy  
    * @Description: TODO 
    * @author Licon  
    * @date 2018 8 16   
    * @version V1.0    
    */  
package com.lss.wy;
  /**  
    * @ClassName: ThreadTest3  
    * @Description: TODO  
    * @author Licon  
    * @date 2018 8 16   
    *    
    */
public class ThreadTest3 extends Thread {
	private  static int i=0;
	private  static Object obj = new Object();
	public ThreadTest3() {
	}

	public ThreadTest3(String no) {
		super(no);
	}
	  /* (！Javadoc)  
	    *   
	    *     
	    * @see java.lang.Thread#run()  
	    */
	@Override
	public void run() {
			String name = Thread.currentThread().getName();
			for (; i < 20000; i++) {
				synchronized (obj) {
					if(i==20000) {
						return;
					}
					System.out.println(name+":"+i);
			}
		}
	}
	public static void main(String[] args) {
		//    start    
		ThreadTest3 t1 = new ThreadTest3("Thread-1");
		t1.start();
		ThreadTest3 t2 = new ThreadTest3("Thread-2");
		t2.start();
		ThreadTest3 t3 = new ThreadTest3("Thread-3");
		t3.start();
		ThreadTest3 t4 = new ThreadTest3("Thread-4");
		t4.start();
		ThreadTest3 t5 = new ThreadTest3("Thread-5");
		t5.start();
		ThreadTest3 t6 = new ThreadTest3("Thread-6");
		t6.start();
		ThreadTest3 t7 = new ThreadTest3("Thread-7");
		t7.start();
		ThreadTest3 t8 = new ThreadTest3("Thread-8");
		t8.start();
	}
}