Question

I have 2 classes e.g. A and B.
These classes have a couple of getter/setter methods with the same name.

Now in the code I do the following:

if(obj.getClassName().equals(A.class.getName())){
   A a = (A) obj;
   String result = a.getInfo();
}
else if(obj.getClassName().equals(B.class.getName())){
   B a = (B) obj;
   String result = a.getInfo();
}

I was wondering if there is a way to call the getInfo avoiding the if statements.
Note: I can not refactor the classes to use inheritence or something else.
I was just interested if there is a trick in java to avoid the if statements.

Answer 1

Unless you want to use reflection, no. Java treats two types which happen to declare the same method (getInfo()) as entirely separate, with entirely separate methods.

If you’ve got commonality, you should be using a common superclass or a common interface that both of them inherit. You’ve tagged the question “design-patterns” – the pattern is to use the tools that the language provides to show commonality.

As Eng.Fouad shows, using instanceof is simpler anyway – and better, as it means your code will still work with subclasses of A or B.

You can isolate this ugliness, of course, by putting it in a single place – either with a facade class which can be constructed from either an A or a B, or by having a single method which performs this check, and then calling that from multiple places.