If a generic type variable is used as a field in a class, should it include the expression? Code Answer

I have a generic type Node:

public class Node<T> {

    private T element;
    private Node<T> next;

    public T getElem() {
        return element;
    }

    public Node<T> getNext() {
        return next;
    }

    public void setElem(T newElem) {
        element = newElem;
    }

    public void setNext(Node<T> n) {
        next = n;
    }
}

And I used it as a field in the class DynamicList:

public class DynamicList<T> implements MyList<T>{
    private Node<T> head;
}

I found that when I used

private Node head;

It won’t affect the list behaviors. So which one is right?

Answer

Seriously it will not effect the behavior, because the types are erased at runtime. But if you do not specifiy a generic type argument, there is no type check and this can lead you to programming mistakes. So the first one is the better solution. If you are using a compiler with the right configurations, it should tell you that you are using the Raw type when writing private Node head;.