In computer science, a linked list is a data structure that is a linear collection of items whose order is not given by their physical placement in memory. Instead, each item links to the next item. The last item links to a terminator used to mark the end of the list.

A singly linked list whose items have two fields: a value and a link to the next item

A doubly linked list whose items have three fields: a value, the link forward to the next item, and the link backward to the previous item

A circular linked list

Item reverseList(Item head) {
    Item prev = null;
    Item curr = head;
    while (curr != null) {
        Item following = curr.next;
        curr.next = prev;
        prev = curr;
        curr = following;
    }
    return prev;
}