Java inheritance - constructors

Question

While studying for my finals, I came across the following statement in the book from which I am currently studying. Considering the following code :

class A         


        

Answer 1

If you have a the base class having a default constructor (no-arg constructor), when you extend B, you don't need to explicitly call super() because it is called any way.

But when you have a constructor with arguments, when making the contructor with parameters in B, you need to pass in super() a parameter for A

example :

class A {
    public A(int x) {   }
  }

  class B extends A {
    public B(int x ) 
    {
       super(x); // need to specify the parameter for class A
       //... 
    }
  }