What is invoking the super class constructor here?

Question

I came across this code while looking for exam prep questions. I don't understand what is invoking the superclass constructor in this code?

The output is ---> feline cougar cc

THL

        public class Feline{

        public String type = "f ";

        public Feline(){
            System.out.print("feline ");
        }
        }

-

    public class Cougar extends Feline {

    public Cougar(){
            System.out.print("cougar ");
    }

    public static void main(String[] args){
            new Cougar().go();                    
    }                                                                                     
    void go(){                            
            type = "c ";                                
            System.out.print(this.type + super.type);
    }
    }

Answer 1

When you have a class that extends some other class, eg Cougar extends Feline, there must be a call to the super class at the top of the constructor. When you don't write one, Java assumes you meant to call the default super class constructor. So your constructor:

public Cougar(){
    System.out.print("cougar ");
}

Is actually interpreted as:

public Cougar(){
     super();
     System.out.print("cougar ");
}

Hence the call to the super class constructor. It's interesting to note that because all classes are extensions of the class Object, there is a call to a super class constructor at the beginning of every constructor that you'll ever write - either an explicit one you've included with or without arguments, or the default super class constructor if you do not specify.