How to execute method on object of Class?>

I wonder is it possible to execute method from class on runtime on object of Class?

At first: I have method that returns me a class:

public static Class<?> getClassById(Long id) throws ClassNotFoundException {
    if(d.id == 1L) {
        return First.class;
    } else if(d.id ==2L) {
        return Second.class;
    } else if(d.id ==3L) {
        return Third.class;
    } else {
        throw new ClassNotFoundException();
    }
}

Second: The way I execute it:

Index.GetClassById(1) which should return me Class. Now I would like to execute method myMethod() from that class. By the way, each class of (First, Second, Third) have this myMethod() method.

Please help.