在创建Java程序时，我遇到了一个问题，

子类构造函数通过调用超类的方法抛出错误

代码类似于以下内容：

class Manage
{
    public static void main(String[] args) 
    {
        Manager m1 = new Manager ( 35 );
    }
}

class Employee
{
        int emp_id;
        public Employee(int id)
        {
                this.emp_id = id;
        }
        public int get_id()
        {
                return emp_id;
        }

}
class Manager extends Employee
{
        public Manager(int id )
        {
                this.emp_id = id ;
        }
}

class Engineer extends Employee
{
        public Engineer(int id)
        {
                this.emp_id = id ;
        }
}

错误是这样的：

$ javac app.java 
app.java:25: cannot find symbol
symbol  : constructor Employee()
location: class Employee
        {
        ^
app.java:33: cannot find symbol
symbol  : constructor Employee()
location: class Employee
        {
        ^
2 errors

为什么会这样？