BJP5, Chapter 16, Programming Projects 3

The implementation of several methods is (or can be) the same between our ArrayList and LinkedList. Write a common abstract superclass called AbstractList that implements the common behavior and is extended by both ArrayList and LinkedList. Factor out the common code from the two list classes into this abstract superclass so that no code duplication occurs between the two. Use iterators wherever possible in the abstract code to ensure that the implementation is efficient for both types of lists.

How should I fix the duplicate between ArrayList and LinkedList?