Account account=new Account(); savethread newfather = new savethread("亲爹", account); savethread oldfather = new savethread("旧爹", account); savethread wildfather = new savethread("野爹", account); spendthread son1 = new spendthread("小红",account); spendthread son2 = new spendthread("小态",account); spendthread son3 = new spendthread("小从",account); spendthread son4 = new spendthread("小蓝",account); newfather.start(); oldfather.start(); wildfather.start(); son1.start(); son2.start(); son3.start(); son4.start();

这段代码中创建了一个 Account 对象，然后分别创建了三个存钱线程 savethread 和四个取钱线程 spendthread，它们共同操作同一个 Account 对象。

其中，savethread 线程通过调用 Account 对象的存钱方法 save() 来增加账户余额，而 spendthread 线程通过调用 Account 对象的取钱方法 spend() 来减少账户余额。

由于多个线程同时对同一个 Account 对象进行操作，可能会出现线程安全问题，比如数据不一致、死锁等问题。因此需要在 Account 对象的存钱和取钱方法中使用 synchronized 关键字，来实现线程安全。

具体实现可以参考如下代码：

class Account {

    private int balance = 0;

    public synchronized void save(int money) {
        balance += money;
        System.out.println(Thread.currentThread().getName() + " 存入 " + money + " 元，余额为：" + balance);
    }

    public synchronized void spend(int money) {
        if (balance >= money) {
            balance -= money;
            System.out.println(Thread.currentThread().getName() + " 取出 " + money + " 元，余额为：" + balance);
        } else {
            System.out.println(Thread.currentThread().getName() + " 余额不足，取款失败！");
        }
    }
}

class savethread extends Thread {

    private Account account;

    public savethread(String name, Account account) {
        super(name);
        this.account = account;
    }

    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            int money = (int) (Math.random() * 1000);
            account.save(money);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

class spendthread extends Thread {

    private Account account;

    public spendthread(String name, Account account) {
        super(name);
        this.account = account;
    }

    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            int money = (int) (Math.random() * 1000);
            account.spend(money);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

public class Main {

    public static void main(String[] args) {
        Account account = new Account();
        savethread newfather = new savethread("亲爹", account);
        savethread oldfather = new savethread("旧爹", account);
        savethread wildfather = new savethread("野爹", account);
        spendthread son1 = new spendthread("小红", account);
        spendthread son2 = new spendthread("小态", account);
        spendthread son3 = new spendthread("小从", account);
        spendthread son4 = new spendthread("小蓝", account);
        newfather.start();
        oldfather.start();
        wildfather.start();
        son1.start();
        son2.start();
        son3.start();
        son4.start();
    }
}