TreeSet isEmpty() method in java

import java.util.TreeSet;
public class TreeSetIsEmptyMethodExample
{
   public static void main(String[] args)
   {
      TreeSet<String> ts = new TreeSet<String>();
      ts.add("violet");
      ts.add("green");
      ts.add("red");
      ts.add("yellow");
      ts.add("blue");
      ts.add("indigo");
      System.out.println("Given TreeSet: " + ts);
      // check for empty TreeSet
      System.out.println("Is TreeSet empty? " + ts.isEmpty());
      // clear TreeSet using clear() method
      ts.clear();
      // again check for empty TreeSet
      System.out.println("Is TreeSet empty? " + ts.isEmpty());
   }
}