Java Set collection

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Set

• Set interface is a sub-interface Collection, Set interface does not provide new methods;
• Set of elements unordered containers implemented in the interface, not repeated, containing up to a null;
• Set a non-thread-safe, but the bottom is achieved using the Map, so you can work to achieve thread-safe Set ConcurrentHashMap by the way;
• Container class implements the Set interface Java API provided are HashSet, TreeSet such as:

Implementation class

• HashSet class
• TreeSet class