Why do I need to write a constructor here explicitly?

Question

This is how I encountered the problem. I am giving an example:

package check;

public class Check {
  int a,b;
  Check (int i,int j) {
    a = i;
    b = j;
         


        

Answer 1

When you create a class, if it has no constructors then Java will provide a default constructor for you. If, however, you have 1 or more constructors, then Java does not provide this default (or zero argument) constructor.

In your subclass, you have not yet created any constructors, so java has provided a default constructor for you. In subclasses, there is an implicit call to super() in the constructor. Since the no argument constructor has not been defined in the super class, Java is effectively trying to invoke a constructor that does not yet exist.