Why a generic like Node<Item> instead of a regular Node [duplicate]

Question

I'm taking Algorithms I on coursera and came across the implementation of a Data Structure called Bag.

However I don't undertand why the use a Node class like this:

private static class Node<Item> { private Item item; private Node<Item> next; }

Why is the Item in there? Why can't I use:

private class Node { private Item item; private Node next; }

Is there a difference? Thanks

What does Item mean in the context of a non-generic world to you? I don't see anywhere that it could be introduced, or what it truly represents. What you've got there is a Node that holds Items, whereas the generic is a Node that can hold literally anything. — Makoto
– Makoto, Commented Feb 4, 2017 at 0:21

OneCricketeer · Accepted Answer · 2017-02-04 00:12:43Z

Yes, there is a difference.

Node<Item> uses what's called a generic. Item in not a class, it's simply an identifier of any element.

Read the Java source code, you would see something like Node<E>... Same thing. Name is not important.

For the other one, you need an Item class to be defined and that is the only datatype a Node can hold

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