IllegalArgumentException from method.invoke

[K Dombroski]

I'm trying to use reflection to call various methods based on values in a properties files.
Here is what I'm trying to accomplish:

 DaoFactory.create<DaoCass>().<methodName>(params, onbhf, d); 

Here is my code:

String daoCall = "create" +config.getDaoName();
String methodName = config.getDaoMethodName();
try {
	//eg. DaoFactory.createGLReportsDao().setupAccountActivity(params, onbhf, d);
	Method method = DaoFactory.class.getMethod(daoCall);
	Method method2 = (method.invoke(null)).getClass().getMethod(methodName, HashMap.class, User.class, Date.class);
	Class c2 = Class.forName(method2.getDeclaringClass().getName());
	method2.invoke(c2,params, onbhf, d);
} catch (Exception e) {
	e.printStackTrace();
	//TODO log exception
}

I keep getting an IllegalArgumentException from my method.invoke call. I have put in output statements, and the methods being called look right. I have tried using

 Class[] parameterTypes = { HashMap.class, User.class, Date.class };   

to pass the parameter types in the getMethod call and then using an Object[] as the 2nd param in the method2.invoke, but that does not work either. I can't figure out what is wrong. The parameter types match what I'm declaring. What could be causing this exception?

Thanks for any help you can provide.

[Wouter Oet]

From the javadoc

IllegalArgumentException - if the method is an instance method and the specified object argument is not an instance of the class or interface declaring the underlying method (or of a subclass or implementor thereof); if the number of actual and formal parameters differ; if an unwrapping conversion for primitive arguments fails; or if, after possible unwrapping, a parameter value cannot be converted to the corresponding formal parameter type by a method invocation conversion.

So i guess that the c2 parameter is not the correct object type. A stacktrace would be useful.

[Christophe Verré]

method.invoke(null)

What is this for ?

[Rob Spoor]

Invoking the static createXXX method; the DaoFactory.create<DaoCass>() part.

The problem is in the invoking of the second method. The first parameter is a Class object, but it should be the instance. Try to change lines 7-9 to this:

Object dao = method.invoke(null); // store a reference because we need it twice
Method method2 = dao.getClass().getMethod(methodName, HashMap.class, User.class, Date.class);
method2.invoke(dao, params, onbhf, d);

[K Dombroski]

Thank you, Rob! That worked!