public class Box<T, S> {
  private T item1;
  private S item2;
  // Constructors, getters, and setters
}
Box<String, Integer> wordAndIntegerBox = new Box<>("Hello", 5);

public class Util {
  public static <T, S> boolean areNumbers(T item1, S item2) {
    return item1 instanceof Number && item2 instanceof Number; 
  }
}
 
boolean areNums = Util.areNumbers("Hello", 34);  // false