How to access subclass method if given Class.class and object reference?

Question

Given the code below:

Parent class:

public class Animal {
  //...
}

Subclasses:

public class Cat extends Animal {
    public void method2(){
        System.out.println("cat method2");
    }
}

public class Dog extends Animal{
    public void method2(){
        System.out.println("dog method2");
    }
}

Enum:

public enum Values {
    VALUE1("v1", Cat.class),
    VALUE2("v2", Dog.class);

    private String val;
    private Class<?> clazz;

    Values(String val, Class<?> clazz){
        this.val = val;
        this.clazz = clazz;
    }

    public String getVal() {
        return val;
    }

    public Class<?> getClazz() {
        return clazz;
    }

}

Main class:

public class Main {
    public static void main(String[] args) {
        Animal a = new Cat();
        method("VALUE1", a);
    }

    public static void method(String val, Animal a){
        Values value = Values.valueOf(val);

        value.getClazz().cast(a).method2();// this doesn't work. how to access method2?
    }
}

The code above won't work. How can I access method2 using Class.class reference? How can I cast The generic Animal class into a subclass given the parameters? If Class.class is not possible, what are the alternatives?

Answer 1

First option, and best option IMO, is to make Animal abstract and add an abstract method2() to Animal . Then you can implement it in Cat and Dog and invoke it without using Reflection. Second option, use reflection.

public static void method(String val, Animal a) {
    Values value = Values.valueOf(val);
    try {
        Method m = value.getClazz().getMethod("method2", null);
        m.invoke(a, null);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

or without Values , because that isn't doing much for you like

public static void method(Animal a) {
    try {
        Method m = a.getClass().getMethod("method2", null);
        m.invoke(a, null);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Both methods output

cat method2