Set Interface in Java

The Set interface extends the Collection interface. A Set is a Collection that cannot contain duplicate elements.

Set Interface in Java:-

The Set interface extends the Collection interface. A Set is a Collection that cannot contain duplicate elements. Not only must these elements be unique, but while they are in the set, each element must not be modified. It permits a single element to be null. The Set interface contains only methods inherited from Collection.

The Collection Framework provides two concrete set implementations: 

1- HashSet

2- TreeSet. 

The HashSet represents a set backed by a hash table providing constant lookup−time access to unordered elements. 

The TreeSet maintains its elements in an ordered fashion within a balanced tree.

The Set interface contains only methods inherited from Collection interface, these are shown  given below:

• add( )
• clear( )
• contains( )
• isEmpty( )
• iterator( )
• remove( )
• size( )

The Example for the Set interface which impliments the TreeSet class ia as-

SetDemo.java

package devmanuals.com;

import java.util.*;

public class SetDemo {
	public static void main(String[] args) {

		Set st = new TreeSet();

		st.add("Gyan");
		st.add("Rohit");
		st.add("Anand");
		st.add("Arunesh");

		Iterator itr = st.iterator();

		while (itr.hasNext()) {
			String str = (String) itr.next();

			System.out.println("Name :" + str);
		}
	}

}

Output:-

Name :Anand Name :Arunesh Name :Gyan Name :Rohit

Download The Code: