用JAVA中的多线程示例银行取款有关问题

用JAVA中的多线程示例银行取款问题
public class Test {   
  public static void main(String[] args) {   
    Account account = new Account();   
    for (int i = 0; i < 1000; i++) {   
      new TestAccount1(account).start();   
      new TestAccount2(account).start();   
    }   
  }   
}   
  
/**  
* @authorleno 账户类 默认有余额，可以取款  
*/  
class Account {   
  private float balance = 1000;   
  
  public float getBalance() {   
    return balance;   
  }   
  
  public void setBalance(float balance) {   
    this.balance = balance;   
  }   
  
  /**  
   * 取款的方法需要同步  
   *   
   * @parammoney  
   */  
  public synchronized void withdrawals(float money) {   
    if (balance >= money) {   
      System.out.println("被取走" + money + "元!");   
      try {   
        Thread.sleep(1);   
      } catch (InterruptedException e) {   
        e.printStackTrace();   
      }   
      balance -= money;   
    } else {   
      System.out.println("对不起,余额不足!");   
    }   
    System.out.println("余额为:" + getBalance() + "元!");   
  }   
}   
  
/**  
* @authorleno 银行卡  
*/  
class TestAccount1 extends Thread {   
  private Account account;   
  
  public TestAccount1(Account account) {   
    this.account = account;   
  }   
  
  @Override  
  public void run() {   
    account.withdrawals(2);   
  }   
}   
  
/**  
* @authorleno 存折  
*/  
class TestAccount2 extends Thread {   
  private Account account;   
  
  public TestAccount2(Account account) {   
    this.account = account;   
  }   
  
  @Override  
  public void run() {   
    account.withdrawals(1);   
  }   
}