NavigableSet headSet() method in Java

// A Java program to demonstrate
// headSet() method of NavigableSet

import java.util.NavigableSet;
import java.util.TreeSet;

public class GFG {
    public static void main(String[] args)
    {
        NavigableSet<Integer> ns = new TreeSet<>();
        ns.add(0);
        ns.add(1);
        ns.add(2);
        ns.add(3);
        ns.add(4);
        ns.add(5);
        ns.add(6);

        System.out.println("Map with key-value less than "+
                        "given argument : " + ns.headSet(6));

        System.out.println("Map with key-value less than or" + 
          " equal to  given argument : " + ns.headSet(6, true));
    }
}

// A Java program to demonstrate
// headSet() method of NavigableSet

import java.util.NavigableSet;
import java.util.TreeSet;

public class GFG {
    public static void main(String[] args)
    {
        NavigableSet<String> ns = new TreeSet<>();
        ns.add("A");
        ns.add("B");
        ns.add("C");
        ns.add("D");
        ns.add("E");
        ns.add("F");
        ns.add("G");

        System.out.println("Map with key-value less than"+
                    " given argument : " + ns.headSet("F"));

        System.out.println("Map with key-value less than "+
           "or equal to given argument : " + ns.headSet("F"));
    }
}