how to call a java method using a variable name?

Question

Say I have Method1(void), Method2(void)...

Is there a way i can chose one of those with a variable?

 String MyVar=2;
 MethodMyVar();

Answer 1

I'm not sure how the accepted answer works for method.invoke() without first argument of static method being null(put dummy value still works though). According to The Java™ Tutorials:

The first argument is the object instance on which this particular method is to be invoked. (If the method is static, the first argument should be null.)

The following shows a complete examples (Main.java), for both static(by class) VS non-static(by instance), plus additional example for method with argument, import necessary class, catch exception, and also superclass method example.

import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;

class Love {
   protected void Method4() {
        System.out.println("calls super protected method by instance");
    }

   public void Method5() {
        System.out.println("calls super public method by instance");
    }
}

class Main extends Love {

    static void Method2(int y) {
        System.out.println("by class: " + y);
    }

    void Method3(String y) {
        System.out.println(y);
    }

    public static void main(String[] args) {

        String MyVar = "2";
        String MyAnotherVar = "3";
        String MySuperVar = "4";
        String MySuperPublicMethodVar = "5";
        Main m = new Main();

       try {
            Method method = Main.class.getDeclaredMethod("Method" + MyVar, int.class); //by class
            Method anotherMethod = m.getClass().getDeclaredMethod("Method" + MyAnotherVar, String.class); //by instance
            Method superMethod = m.getClass().getSuperclass().getDeclaredMethod("Method" + MySuperVar); //super method by instance, can be protected
            Method superPublicMethod = m.getClass().getMethod("Method" + MySuperPublicMethodVar); //getMethod() require method defined with public, so even though sublcass calls super protected method will not works
            try {
                method.invoke(null, 10000);//by class
                anotherMethod.invoke(m, "by instance"); //by instance
                superMethod.invoke(m); //super method by instance
                superPublicMethod.invoke(m); //super's public method by instance
            } catch (InvocationTargetException e) {
                throw new RuntimeException(e);
            }

       } catch (NoSuchMethodException e) {
           throw new RuntimeException(e);
       } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
       }
    }
}

Output:

$ javac Main.java
$ java Main 
by class: 10000
by instance
calls super protected method by instance
calls super public method by instance
$