java - Cannot access class methods via generics

Question

I changed my method to generic method. What is happening now is that I was deserializing the class inside the methodB and accessing its methods which I can not do anymore.

<T> void methodB(Class<T> clazz) {
    T var;
    HashMap<String, T> hash = new HashMap<>();
}

void methodA () {
  methodB(classA.class);
}

Initially inside methodB with no generics,

var = mapper.convertValue(iter.next(), ClassA.class);
var.blah() //works fine

After using generics,

var = mapper.convertValue(iter.next(), clazz);
var.blah() //cannot resolve the method.

How do I access blah() method of classA?

Answer 1

I think you should use interfaces instead of generics, if you want to call the same 'blah' function on a variety of classes (A,X,Y,Z) (each of which has the same function signature)..

Your other option (if you cannot modify A, e.t.c) is to use reflection. read more about this in https://docs.oracle.com/javase/tutorial/reflect/