Cannot reference this before supertype constructor has been called

Question

I\'m attempting to implement a circular queue class in Java. And in doing so I had to created a node class to group together elements and pointers to the next node. Being ci

Answer 1

You cannot refer tho this (or super) in a constructor, so you should change your code like this:

public class Node<Key>{
    private Key key;
    private Node<Key> next;
    public Node(){
    key = null;
        next = this;
    }
    public Node(final Key k){
    key = null;
        next = this;
    }
    public Node(final Key k, final Node<Key> node){
        key = k;
        next = node;
    }
    public boolean isEmpty(){return key == null;}
    public Key getKey(){return key;}
    public void setKey(final Key k){key = k;}
    public Node<Key> getNext(){return next;}
    public void setNext(final Node<Key> n){next = n;}
}

Answer 2

Can not pass "this" as a parameter to call the constructor.

Answer 3

The compile error is

Cannot refer to 'this' nor 'super' while explicitly invoking a constructor

Basically, you cannot use "this" from inside "this(...)"

Answer 4

You dont need to pass it in all cases. since you can refer to it in the other construtor