How to implement a linked list in Java without using pointers?

In Java, object references can be used to implement linked list data structures without the need for direct pointers.

Each node in the linked list is an object that includes a data field and a reference to the next node. Initially, define a linked list node class, for example:

public class ListNode {
    public int val;
    public ListNode next;

    public ListNode(int val) {
        this.val = val;
        this.next = null;
    }
}

Then, this node class can be used to create a linked list by connecting the nodes with references. For example, create a linked list with three nodes.

ListNode head = new ListNode(1);
ListNode second = new ListNode(2);
ListNode third = new ListNode(3);

head.next = second;
second.next = third;

This creates a linked list with three nodes, each node containing a value of 1, 2, or 3. You can access and manipulate the nodes by traversing the list.

It is worth noting that, in Java, the implementation of linked lists does not require manual memory management because Java has an automatic memory management mechanism (garbage collector) that can automatically reclaim objects that are no longer in use.