关于java实用集合实现一银行系统

大综合题：使用集合实现银行管理系统，要求如下：（60分钟）
1) 定义bank类
属性有银行名称和存放客户的ArrayList集合，有开户方法、销户方法、存钱方法、取钱方法、转账方法（本行转账、跨行转账）
2) 定义customer类
属性有账户名、密码、余额
3) 定义测试类

创建一个银行集合用于存放bank对象
创建几个bank对象：分别叫华夏银行、工商银行、招商银行
将bank对象存入银行集合

public class Bank {

            private String name;
     private ArrayList<Customer> customers;

            public Bank(String n) {
                name = n;
                    customers = new ArrayList<>();
            }

            public Customer openAccount(String na, String ps, double money) {
                Customer c = new Customer(na,ps, money);
                    customers.add(c);
            }

            publlic Customer dropAccount(Customer c) {
               Customer ret = null;
               int idx = customers.indexOf(c);
                 if (idx != -1) {
                    ret = customes.get(idx);
                        customers.remove(idx);
                }

                return ret;
            }


            public Customer deposit(String n, double money) {
                Customer ret = new Customer(n, "", 0);
                    int idx = customers.indexOf(ret);
                    if (idx != -1) {
                      ret = customers.get(idx);
                        ret.money += money;
                    }

                    return ret;
            }

            public Customer withdraw(String n, String p, double m) {
                Customer t = new Customer(n, '', -1d);

                    int idx = customers.indexOf(t);
                    if (idx != -1) {
                      Customer c = customers.get(idx);
                        if (c.password.equals(p) && c.money >= m) {
                              c.money -= m;
                        }
                        return c;
                    }

                    return t;
                }

                ...
                ;;;
        }