extends makes one class a more specific version of another. class Mentor extends Person says a mentor is a person and can use the person fields and methods. Java allows only one superclass.
super calls the superclass constructor or a superclass method. The super constructor call must be the first line of your constructor when you write it. If you omit it, Java inserts super() and the superclass must have a no-argument constructor.
Example
super(name) stores the name in Person. Mentor does not declare name again. It inherits the field.
class Person {
String name;
Person(String name) { this.name = name; }
}
class Mentor extends Person {
Mentor(String name) { super(name); }
}
public class Inherit {
public static void main(String[] args) {
Mentor m = new Mentor("Anitha");
System.out.println(m.name);
}
}Put shared fields in the superclass only when every subclass truly has them. A field that only a mentor needs belongs on Mentor, not on Person.
