Throw a JsonProcessingException

Question

I am trying to throw a JsonProcessingException that will be thrown by a mock object.

when(mapper.writeValueAsString(any(Object.class))).thenThrow(new JsonProcessingException("Error")); 

However, I cannot create a JsonProcessingException object, since all the constructors are protected. How do I get around this?

Answer 1

how about throwing an anonymous exception like JsonProcessingException

 when(mapper.writeValueAsString(any(Object.class))).thenThrow(new JsonProcessingException("Error"){}); 

The braces {} do the trick. This is much better since it does not confuse the reader of the test code.

Answer 2

How about throwing one of the famous direct subclasses?

for v1.0

 Direct Known Subclasses: JsonGenerationException, JsonMappingException, JsonParseException 

for v2.0

 Direct Known Subclasses: JsonGenerationException, JsonParseException 

Answer 3

This worked for me, which allowed a JsonProcessingException to be thrown

 doThrow(JsonProcessingException.class).when(mockedObjectMapper).writeValueAsString(Mockito.any()); 

Answer 4

Try using thenAnswer and create an anonymous class from JsonProcessingException

 when(mapper.writeValueAsString(any(Object.class))).thenAnswer(x-> {throw new JsonProcessingException(""){};});