···
package niub;

public class piaozi {
public static int count = 50 ;
}

···
···
package niub;

public class piaozi01 {

public static void main(String[] args) {
Runnable mythread = new Runnable() {
@Override
public void run() {
synchronized (this){
System.out.println(Thread.currentThread().getName()
+ "卖出了一张票，还剩：" + (--piaozi.count) + "张"
);
}

        }
    };
    new Thread(mythread, "线路1").start();
    new Thread(mythread, "线路2").start();
    new Thread(mythread, "线路3").start();
    new Thread(mythread, "线路4").start();
    new Thread(mythread, "线路5").start();
}

···