how to implement HashCode() for a node containing only reference to next node?

Question

public class Node {
    private Node nextNode;

    @Override
    public int hashCode() {
        //How to implement this?
        //Because you just have a attribute which is a reference.
        //I think the attribute is almost useless, because if you use the HashCode of the attribute, you will finally fall into a useless loop.
        //Thus, I think you should find a way to represent the HashCode of reference (instance) itself.
    }
}

From the comment in the code, my question is actually how to uniquely identify reference itself, like address in C.

Answer 1

There is nothing you need to do here, the Node already has the default implementation which returns a hash code based on the memory location it resides at.