Classcast exception when using mockito

Question

I am getting classcast exception using the following bit of code in Test case.

  Employee employee1= new Employee();
  Employee employee2= new Employee();
  Employee employee3= new Employee();
  int id=1234;

  when(employee1.getID()).thenReturn(id);
  when(employee2.getID()).thenReturn(id);
  when(employee3.getID()).thenReturn(id);

I want to generalize this as

 when((((Employee)Matchers.any(Employee.class)).getID())).thenReturn(id);

Am I doing anything wrong?

java.lang.ClassCastException: org.hamcrest.core.IsInstanceOf cannot be cast to com.site.model.Employee

score 3 · Answer 1 · answered Oct 10 '18 at 10:25

Hi I know this is a very old question however I just got to this same problem myself today.

Anyway it has to do with how hamcrest handles Matchers. I basically doesn't return the given type but a wrapper around it.

The easiest way to fix it is to use any from mockito not hamcrest e.g.

when((((Employee)org.mockito.Matchers.any(Employee.class)).getID())).thenReturn(id);

For more details see this answer: comparison with mockito and hamcrest matchers

Hope it helps anyone stumbling through this ;)

Cool answer! The only change is to use `org.mockito.ArgumentMatchers.any` as `org.mockito.Matchers.any` is deprecated. — jumping_monkey, May 28 '21 at 10:31

score 1 · Answer 2 · answered Aug 04 '14 at 14:31

1

If you find that you need to typecast when using Mockito then you usually have something wrong.

I guess you are trying to do something like:

    Employee employee = Mockito.mock(Employee.class);
    when(employee.getId()).thenReturn(id);

answered Aug 04 '14 at 14:31

Steve C

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Here employee is not fixed. I need to return same thing for the instance employee1 or employee2. Can you suggest how to do that – Patan Aug 04 '14 at 14:37
You should show more of your test code so that we can get some context – Steve C Aug 04 '14 at 14:40
Sorry for limited information. I have updated the question. Can you help me. – Patan Aug 04 '14 at 14:57
1

What piece of logic are you trying to test? – Steve C Aug 04 '14 at 15:27
It shall be independent of logic. I just need to return a constant value when the method is being invoked for all test cases. – Patan Aug 04 '14 at 16:10

Classcast exception when using mockito

2 Answers2