I have the following problem: implicit super constructor is undefined must invoke another constructor java. I have two classes one which inherits and calls the super - Method.
Person-Class:
public class Person {
private String firstName;
private String name;
private Date birthday;
private Gender gender = Gender.Unknown;
Person(String fn, String n, Date d, Gender g){
firstName = fn;
name = n;
birthday = d;
gender = g;
}
Person(Person p){
firstName = p.firstName;
name = p.name;
birthday = new Date(p.birthday);
gender = p.gender;
}
Person(String fn, String n){
firstName = fn;
name = n;
}
And the second Class:
public class Student extends Person implements Noten {
private int nr;
private String st;
Student(int m, String s){
this.nr= m;
this.st= s;
}
Student(Person p) {
super(p);
// TODO Auto-generated constructor stub
}
Why upon extending to class Person, Student class must implement Stundet(Person p) - Method?
One Solution: Add a Person() - Method to the Person-Class:
Person(){
System.out,println("Hello World"};
Still doesn't work.
First Question: Why does the super(p) - Method doesn't work?
Second Question: How do i make it work even without adding a Person() - with no Parameters to the Person-Class?
Third Question: Why didn't adding Person() - work?
First Question: Why does the super(p) - Method doesn't work?
It works fine, in that second Student constructor.
Second Question: How do i make it work even without adding a Person() - with no Parameters to the Person-Class?
You need to call one of the Person constructors using the super(...) syntax in that first Student constructor, because you must provide at least a firstName and a name.
Third Question: Why didn't adding Person() - work?
Added a no-argument constructor to Person does work, since the compiler can now implicitly call that Person constructor in the first Student constructor.