TreeSet Class in Java

Example : Program to implement different methods in TreeSet

import java.util.*;
public class TreeSetDemo
{
      public static void main(String args[])
      {
            TreeSet<String> ts = new TreeSet<String>();
            System.out.println("Intial size of TreeSet: "+ts.size());
            
            //adding the elements
            ts.add("ZZ");
            ts.add("AA");
            ts.add("BB");
            ts.add("CC");
            ts.add("DD");
            ts.add("CC");

            //ts.add(null); gives NullPointerException
            System.out.println("TreeSet elements after adding: "+ts);
            System.out.println("TreeSet is empty: "+ts.isEmpty());
            System.out.println("Size of TreeSet : "+ts.size());

            //delete the elements
            ts.remove("BB");
            System.out.println("TreeSet elemnts after deletion: "+ts);
      }
}