Run a java method by passing class name and method name as parameter

Question

I am trying to make a program that executes a particular method when the class name and method name are passed as String parameter to the caller. Consider the code below. I

Answer 1

If all you are trying to do is call a method by name, you don't need to cast it to anything. It is sufficient to use the Object with further reflection.

See Class.getDeclaredMethod(), as in:

Object carObj = ...;
Method method = carObj.getClass().getDeclaredMethod(methodName, ...);
Object retObj = method.invoke(carObj, ...);

Note that we don't care what type carObj actually is, although if you wanted to check you could always use instanceof or Class.isAssignableFrom or Class.isInstance.

It is a bit weird, though, that you are instantiating a new object then calling one of its methods all in one go. That object goes away once your runTheMethod returns.

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By the way, it looks like you're just trying to get and set bean properties. You might want to have a look at Apache Commons BeanUtils instead, then your example becomes simply:

CarBean bean = ...;
String color = (String)PropertyUtils.getSimpleProperty(bean, "color"); // calls getter.