An object that can be an element in a LinkedList.
All elements of a LinkedList
must extend this class.
The class provides the internal links that link elements together
in the LinkedList
, and a reference to the linked list itself
that an element is currently part of.
An entry can be in at most one linked list at a time.
While an entry is in a linked list, the list property points to that
linked list, and otherwise the list
property is null
.
When created, an entry is not in any linked list.