[Java] Set Implementations

Documents: https://docs.oracle.com/javase/tutorial/collections/implementations/set.html


There are three general-purpose Set implementations:

• HashSet
• No ordering guarantees.
• TreeSet
• Implements SortedSet interface
• LinkedHashSet
• Differs from HashSet in that it maintains a doubly-linked list running through all of its entries. 
• This linked list defines the iteration ordering, which is the order in which elements were inserted into the set (insertion-order).

There are two special-purpose Set implementations:

• EnumSet
• CopyOnWriteArraySet