The Set Interface : java collection interface that guarantees no duplicates as well as preservation of insertion order

The Java platform contains three general purpose Set implementations: HashSet, TreeSet, and LinkedHashSet. HashSet, which stores its elements in a hash table, is the best-performing implementation; however it makes no guarantees concerning the order of iteration. TreeSet, which stores its elements in a red-black tree, orders its elements based on their values; it is substantially slower than HashSet.LinkedHashSet, which is implemented as a hash table with a linked list running through it, orders its elements based on the order in which they were inserted into the set (insertion-order). LinkedHashSetspares its clients from the unspecified, generally chaotic ordering provided by HashSet at a cost that is only slightly higher.


You could try to build it by combining Set and List. Any collection implementing Set should not allow duplicate elements, and any collection implementing List should maintain order.

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