Mocking java objects gives class cast exceptions

Question

I have a interface fly and a class duck which implements fly.

interface Fly {
  getWingSize();   
}

public class Duck implements Fly {
  @Override
  int getWingSize(){
    return 1;
  }
}

In my controller class, when I try to use the following:

Fly flyAnimal = Animal.getFlyingAnimal();
((Duck) flyAnimal).getWingSize();

It works fine, however in my junit, it gives a class cast exception. I am using powermockito.

You should be using capitalized names for your classes, e.g. `interface Fly`. — Tim Biegeleisen, Jul 08 '15 at 02:01
yes, i am using capitalized names. i cant use the code on stackoverflow, hence i had to make up a code that was somewhat similar to what I am dealing with — mistack305, Jul 08 '15 at 03:06

score 1 · Answer 1 · answered Jul 08 '15 at 02:27

1

In your code you are casting to concrete class (duck). In general, you would mock interfaces. Your test case might have mocked interface fly.

It should work fine if you replace ((duck) fly).getWingSize(); with fly.getWingSize();

answered Jul 08 '15 at 02:27

Naresh Vavilala

I am having issues with my junit, i am using mockito – mistack305 Jul 08 '15 at 03:13
please post your test case. – Naresh Vavilala Jul 08 '15 at 03:54
Duck duckAnimal = PowerMockito.mock(duck.class); PowerMockito.when(duckAnimal. getWingSize()).thenReturn(1); – mistack305 Jul 08 '15 at 04:46
@mistack305 instead of making random stuff up paste by editing your question a real replicatble problem. There is no casting going on here in what you have posted. You can not get the exception you are saying you are getting. – Shahzeb Jul 08 '15 at 04:59

1 Answers1