HashSet in Java

Java HashSet class creates a collection that uses a hash table for storage. HashSet only contains unique elements and it inherits the AbstractSet class and implements the Set interface. Also, it uses a mechanism hashing to store the elements. 
```Java
import java.util. * ;

public class MyHashset {
	public static void main(String args[]) {
		HashSet < String > s = new HashSet();
		s.add("a");
		s.add("c");
		s.add("b");
		Iterator < String > itr = s.iterator();
		while (itr.hasNext()) {
			System.out.println(itr.next());
		}
	}
}
```
Below are some of the methods of the Java HashSet class:
Method | Description
---- | -----
 boolean add(Object o) | Adds the specified element to this set if it is not already present.
 boolean contains(Object o) | Returns true if the set contains the specified element.
 void clear() | Removes all the elements from the set.
 boolean isEmpty() | Returns true if the set contains no elements.
 boolean remove(Object o) | Remove the specified element from the set.
 Object clone() | Returns a shallow copy of the HashSet instance: the elements themselves are not cloned.
 Iterator iterator() | Returns an iterator over the elements in this set.
 int size() | Return the number of elements in the set.
Home