package LinkedList;

public class Linkedlist<T> {
    private int size;
    Node head;
    Node tail;

    public Linkedlist() {// default constructor
        size = 0;
        head = null;
        tail = null;
    }

    public class Node {// Node class
        T data;// current node data
        Node next;// reference to next node
        Node prev;// reference to previous node

        public Node(T data) {// def constructor
            this.data = data;
            next = null;
            prev = null;
        }

        @Override // to check equality of two nodes
        public boolean equals(Object obj) {
            if (this == obj)// checks if both have same reference
                return true;
            if (obj == null ||this==null || this.getClass() != obj.getClass())
                return false;
            @SuppressWarnings("unchecked")//casting obj to node gives a unchecked cast warning.
            Node n=((Node)obj);
            if(!(this.data==n.data))
                return false;
            return true; 
        }

As in the code above, I have a generic class Linkedlist which nests a Node class. The functionality of the code is very obvious, I'm trying to create a doubly linked list.

The problem is that in the equals function in the Node class, I am typecasting the object obj to a Node which gives an unchecked cast warning which I have currently suppressed. The autogenerated equals function from Visual Studio Code gives this same warning. I know that this warning must mean that my code can somehow break during runtime, but I don't know how and I am new to generics and programming in general. Is there any way to resolve this warning?

CodePudding user response：

You could use this to avoid the cast warning

if (!(obj instanceof LinkedList<?>.Node)) return false;
LinkedList<?>.Node node = (LinkedList<?>.Node) obj;