help me me me me me

Employee类

 * @Author ChenJiahao(程序员五条)
 * @Date 2021/9/21 19:28
 */
public class Employee implements Comparable<Employee>{
    private int id;
    private String name;
    private double salary;

    public Employee() {
    }

    public Employee(int id, String name, double salary) {
        this.id = id;
        this.name = name;
        this.salary = salary;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getSalary() {
        return salary;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", salary=" + salary +
                '}';
    }

    @Override
    public int compareTo(Employee o) {
        if(this.id < o.id){
            return -1;
        }else if (this.id > o.id){
            return 1;
        }else{
            return 0;
        }
    }
}

Manager类

/**
 * @Author ChenJiahao(程序员五条)
 * @Date 2021/9/21 19:30
 */
public class Manager extends Employee {
    private double bonus;

    public Manager() {
    }

    public Manager(int id, String name, double salary, double bonus) {
        super(id, name, salary);
        this.bonus = bonus;
    }

    public double getBonus() {
        return bonus;
    }

    public void setBonus(double bonus) {
        this.bonus = bonus;
    }

    @Override
    public double getSalary() {
        return super.getSalary() + this.bonus;
    }

    @Override
    public String toString() {
        return "Manager{" +
                "bonus=" + bonus +
                '}';
    }
}

第四个问题不知道你具体是想干嘛