In List API:

• List<E> is the base interface for all kinds of list. It defines general operations for a List type.
• Abstract subclasses: AbstractList<E> and AbstractSequentialList<E>
• Concrete implementation classes: ArrayList<E>, Vector<E>, LinkedList<E> and CopyOnWriteArrayList<E>(this class is under java.util.concurrent package).
• Legacy collection: Vector<E>
• Implementation classes in JDK which are not members of Java Collections Framework: AttributeList,RoleList, RoleUnresolvedList and Stack.

The following class diagram describes the hierarchy structure of List API in Java Collections Framework: