Difference between HashSet and TreeSet

Feature	HashSet	TreeSet
Definition	HashSet is an implementation of the Set interface. It stores unique elements (no duplicates).	TreeSet is an ordered version of HashSet. It maintains the insertion order of elements.
Duplicates	HashSet does not allow duplicate elements.	TreeSet also does not allow duplicate elements.
Ordering	HashSet does not maintain any specific order of elements.	TreeSet maintains the insertion order of elements.
Null Values	HashSet allows a single null value.	TreeSet allows a single null value.
Implementation	HashSet uses a hash table for storage.	TreeSet uses a balanced binary search tree (usually a red-black tree) for storage.
Example	java Set<String> names = new HashSet<>(); names.add(“Alice”); names.add(“Bob”); names.add(“Charlie”); System.out.println(names);	java Set<String> names = new TreeSet<>(); names.add(“Alice”); names.add(“Bob”); names.add(“Charlie”); System.out.println(names);

In the examples above, HashSet stores unique names, while TreeSet maintains the insertion order of names. Remember that HashSet is ideal for maintaining a collection of unique elements, while TreeSet is useful when order matters.

Homepage

Readmore