Java - Set Interface

Source Link:
https://www.tutorialspoint.com/java/java_set_interface.htm

Some Useful Methods:

add( )
Adds an object to the collection.

clear( )
Removes all objects from the collection.

contains( )
Returns true if a specified object is an element within the collection.

isEmpty( )
Returns true if the collection has no elements.

remove( )
Removes a specified object from the collection.

size( )
Returns the number of elements in the collection.

Example: 
import java.util.*;

public class SetDemo {

  public static void main(String args[]) { 
      int count[] = {34, 22,10,60,30,22};

      Set<Integer> set = new HashSet<Integer>();

      try {
         for(int i = 0; i < 5; i++) {
            set.add(count[i]);
         }
         System.out.println(set);
         TreeSet sortedSet = new TreeSet<Integer>(set);
         System.out.println("The sorted list is:");
         System.out.println(sortedSet);

         System.out.println("The First element of the set is: "+ (Integer)sortedSet.first());
         System.out.println("The last element of the set is: "+ (Integer)sortedSet.last());
      }
      catch(Exception e) {}
   }
} 

This will produce the following result − 
[34, 22, 10, 60, 30] 
The sorted list is: 
[10, 22, 30, 34, 60] 
The First element of the set is: 10 
The last element of the set is: 60