Java相关题目，求助！

如题所述

public class Test{
public static void main(String[] args) {
//5个线程代表5个售票员
SaleTickets t1=new SaleTickets();
SaleTickets t2=new SaleTickets();
SaleTickets t3=new SaleTickets();
SaleTickets t4=new SaleTickets();
SaleTickets t5=new SaleTickets();

t1.setName("售票员1");
t2.setName("售票员2");
t3.setName("售票员3");
t4.setName("售票员4");
t5.setName("售票员5");

t1.start();
t2.start();
t3.start();
t4.start();
t5.start();
}
}
class SaleTickets extends Thread{
//总票数
public static int tickets=100;

@Override
public void run() {
for(int i=0;i<20;i++){
System.out.println(this.getName()+"卖出"+tickets+"号票");
tickets--;
}
}
}