解决Java泛型嵌套类类型转换的Unchecked Cast警告

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)
                return false;

            // 使用 instanceof 检查类型
            if (!(obj instanceof Linkedlist<?>.Node)) {
                return false;
            }

            // 类型转换前已经确认类型，避免 Unchecked Cast 警告
            Linkedlist<?>.Node otherNode = (Linkedlist<?>.Node) obj;

            if (this.data == null && otherNode.data != null) {
                return false;
            }
            if (this.data != null && !this.data.equals(otherNode.data)) {
                return false;
            }
            if (this.data == null && otherNode.data == null) {
                return true;
            }
            return true;
        }
    }
}