How to make mock to void methods with Mockito

Call Real Method

Mock not void method:

Mockito.when(jsonResponseValidator.validate(any(DefaultResponse.class))).thenCallRealMethod()

Mock void method:

Mockito.doCallRealMethod().when(jsonResponseValidator).validate(any(DefaultResponse.class));

You can use any of the doReturn(), doThrow(), doAnswer(),doNothing(), doCallRealMethod() family of methods.

Do Throw

Mock void method with doThrow():

...

@Mock
privare TransferSender transferSender;

...
Transfer transfer = new Transfer();
Mockito.doThrow(new MyException("kabooom!").when(transferSender).send(transfer);

source: Mockito API