顾客存钱到银行

package com.thread;
class Bank{
private int sum;
Object object = new Object();
public void add(int n ){
synchronized (object) {
sum =sum+n;
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("银行的钱-->"+sum);
}
}
}
public class Cus implements Runnable {
private Bank bank = new Bank();
@Override
public void run() {
for (int i = 0; i < 3; i++) {
bank.add(100);
}

}
public static void main(String[] args) {
Cus cus = new Cus();
Thread t1 = new Thread(cus);
Thread t2 = new Thread(cus);
t1.start();
t2.start();
}
}