Why should I call super() in Java?

Question

I see an example from a book that I read about java:

public class A{
  public A(){
      System.out.println(\"A\");
   }
}

public class B extends A{
    public          


        

Answer 1

The first thing that happens in any constructor is a call to this() or super(); There is no harm putting in empty super(), but if you dont the compiler will generate it.
An explicit call is only necessary when the constructor of the superclass takes parameters.

class Parent{
Parent(String s1){

}
}

class Child extends Parent{
Child(String s1,String s2){
super(s1);
this.s2=s2;
}
}