Is it okay for a class to have a field of its own type

Question

I did the following, i got a stackoverflow error after some time, and I understand why it was.

public class Cat {
    String name=\"default name\";
    Cat i         


        

Answer 1

There are many examples of self referencing data structures that are valid. Think of a LinkedList. Each LinkNode has a data field, and a pointer to the next LinkNode.

class LinkNode {
    int data;
    LinkNode nextLink;

    public LinkNode(int d1) {
        data = d1;
        nextLink = null;
    }
    ...
}

class LinkedList {
    private LinkNode first;
...
}

Your StackOverflow problem stems from the fact that creating an instead of X requires the creation of another X, ad-infinitum.

Just think of your Cat example. Why would instantiating a Cat require of all things...another Cat!