Difference between HashSet and TreeSet

Difference between HashSet and TreeSet

	HashSet	TreeSet
Ordering	Stores the object in random order. There is no guarantee to output as insertion order.	Elements are sorted according to the natural ordering of its elements in TreeSet. We can use comparator to sort the elements.
Null value	HashSet can store null object.	Storing the null object in TreeSet object, it will throw NullPointer Exception.
Performance	HashSet take constant time performance for the basic operations like add, remove contains and  size.	TreeSet guarantees log(n) time cost for the basic operations (add,remove,contains).
Speed	HashSet is much faster than TreeSet, as time complexity  of HashSet is constant. Iteration performance of HashSet mainly depends on the load factor and initial capacity parameters.	Slow because most of operation in log(n) time complexity. (add,remove, contains and size).
Internal implementation	HashSet are internally backed by hashmap.	TreeSet is backed by a  Navigable  TreeMap.
Functionality		Methods pollFirst(), pollLast(), first(), last(), ceiling(), lower() etc. makes TreeSet rich in functionality.
Comparision	HashSet uses equals() method for comparison in java.	TreeSet uses compareTo() method for maintaining ordering.