请问这个银行账户的代码是不是遵从了封装原则呢?有什么错误或建议呢?

要求如下:自定义一个银行账户类,包括属性(用户名,账号,余额)以及方法(存钱、取钱、加利息、查询余额)。遵从封装原则。 创建两个用户对象,
模拟两个用户的各3次交易,例如:取钱,存钱,查询余额。
创建账户所需的信息由键盘输入;存钱、取钱的数额由随机数模拟,随机数上限为10,000。每次账户交易在屏幕打印交易后的账户信息

public class Transactions
{
public static class Bankaccount {
private final double RATE=0.05;
private String name;
private int accountnumber;
private double balance;

    public Bankaccount(String username,int accountnumber,double balance)
    {
        name=username;
        this.accountnumber=accountnumber;
        this.balance=balance;
    }
    /////////////////////////////////

//查询余额
    public double getbalance() {
        return balance;
    }
//存钱
    public double deposit(double amount) 
    {
        balance+=amount;
        return balance;

    }
//取钱
    public double withdraw(double amount) {
        balance-=amount;
        return balance;
    }
//利息
    public double addinterest() {
        balance*=1+RATE;
        return balance;
    }
    public String toString(){
        NumberFormat fmt=NumberFormat.getCurrencyInstance();
        return accountnumber+"\t"+name+"\t"+fmt.format(balance);
    }
}
public static void main(String[] args) 
{
    Random g=new Random();

    Bankaccount user1=new Bankaccount("xiaoming",001,20);
    Bankaccount user2=new Bankaccount("xiaohua",002,50);

    user1.deposit(g.nextDouble()*10000+1);
    System.out.println(user1);
    user1.withdraw(g.nextDouble()*10000+1);
    System.out.println(user1);
    user1.getbalance();
    System.out.println(user1);
    user2.deposit(g.nextDouble()*10000+1);
    System.out.println(user2);
    user2.withdraw(g.nextDouble()*10000+1);
    System.out.println(user2);
    user2.getbalance();
    System.out.println(user2);

}
//
}

static class Bankaccount
这里不应该用静态类
并且Bankaccount 应该独立,而不是放在 Transactions里。因为调用者和被调用者毫无关系。