Java Generic Method with both return type and generic type

import java.util.HashSet;
import java.util.Set;

public class Main {
  public static <T> boolean isSubset(Set<T> s1, Set<T> s2) {
    return s1.containsAll(s2);
  }/*from ww  w  .j  a v  a  2  s  .  com*/

  public static void main(String[] args) {
    Set<String> s1 = new HashSet<>();
    s1.add("HTML");
    s1.add("CSS");
    s1.add("XML");

    Set<String> s2 = new HashSet<>();

    s2.add("XML");
    s2.add("CSS");

    System.out.println(s1);
    System.out.println(s2);

    boolean s3 = isSubset(s1, s2);

    System.out.println(s3);

    s3 = isSubset(s2, s1);

    System.out.println(s3);
  }
}