mockito: NullPointerException in java.lang.reflect.Method.getParameterTypes

Trying to upgrade Mockito from 3.4.6 (3.4.8 wasn’t published to Maven central) to anything 3.5.x (3.5.7 included) and I get some weird NPEs, which don’t happen if I run each test on its own:

[INFO] Running core.rest.exception.mapper.NotFoundExceptionMapperTest
07:22:56.767 [main] WARN  core.rest.exception.mapper.NotFoundExceptionMapper - Endpoint not found for path: http://host:8080/404
[ERROR] Tests run: 3, Failures: 0, Errors: 2, Skipped: 0, Time elapsed: 0.019 s <<< FAILURE! - in core.rest.exception.mapper.NotFoundExceptionMapperTest
[ERROR] testExceptionCreatesServerErrorResponseWhenEndpointWasNotMatchedAndIsServiceRequest  Time elapsed: 0.012 s  <<< ERROR!
java.lang.NullPointerException
        at java.base/java.lang.reflect.Method.getParameterTypes(Method.java:311)
        at org.mockito.internal.creation.DelegatingMethod.<init>(DelegatingMethod.java:20)
        at org.mockito.internal.invocation.DefaultInvocationFactory.createMockitoMethod(DefaultInvocationFactory.java:80)
        at org.mockito.internal.invocation.DefaultInvocationFactory.createInvocation(DefaultInvocationFactory.java:59)
        at org.mockito.internal.creation.bytebuddy.MockMethodInterceptor.doIntercept(MockMethodInterceptor.java:58)
        at org.mockito.internal.creation.bytebuddy.MockMethodInterceptor.doIntercept(MockMethodInterceptor.java:47)
        at org.mockito.internal.creation.bytebuddy.MockMethodInterceptor$DispatcherDefaultingToRealMethod.interceptAbstract(MockMethodInterceptor.java:129)
        at org.mockito.codegen.HttpHeaders$MockitoMock$2122467463.getHeaderString(Unknown Source)
        at core.rest.exception.mapper.NotFoundExceptionMapper.isServiceRequest(NotFoundExceptionMapper.java:56)
        at core.rest.exception.mapper.NotFoundExceptionMapper.getResponseBuilder(NotFoundExceptionMapper.java:48)
        at core.rest.exception.mapper.NotFoundExceptionMapper.getResponseBuilder(NotFoundExceptionMapper.java:13)
        at core.rest.exception.mapper.BaseExceptionMapper.getResponse(BaseExceptionMapper.java:33)
        at core.rest.exception.mapper.BaseExceptionMapper.toResponse(BaseExceptionMapper.java:28)
        at core.rest.exception.mapper.NotFoundExceptionMapperTest.testExceptionCreatesServerErrorResponseWhenEndpointWasNotMatchedAndIsServiceRequest(NotFoundExceptionMapperTest.java:43)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

Initially I thought it might be caused by the new MockedStatic usage, but I’ve marked those classes with @Disable and the exceptions happen anyway and the test classes that are affected weren’t using MockedStatic anyway, so I’m not exactly sure how to investigate this further.

About this issue

Original URL
State: closed
Created 4 years ago
Reactions: 4
Comments: 34 (11 by maintainers)

Commits related to this issue

Me dpc 3494 part 2 upgrade mockito (#1911) ## 🎫 Ticket https://jira.cms.gov/browse/DPC-3494 ## 🛠 Changes Updated Mockito from 3.4.6 to 5.4.0. Removed mocking of Method class from FHIRRequ... — committed to CMSgov/dpc-app by MEspositoE14s a year ago

Most upvoted comments

@TimvdLippe In my case I’m mocking also my own classes and get the same NPE. What can we do to help you to solve this issue ?

I don’t know if it helps but in Java 15 I got this log :

[ERROR] getCurrentCallContext_should_return  Time elapsed: 0.001 s  <<< ERROR!
java.lang.NullPointerException: Cannot invoke "[Ljava.lang.Class;.clone()" because "this.parameterTypes" is null
	at ch.mobi.jap.context.callcontext.internal.DefaultCallContextManagerTest.getCurrentCallContext_should_return(DefaultCallContextManagerTest.java:91)

McKratt on Jan 12, 2021

A temporary workaround is to fork each test, though build times suffer somewhat.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>3.0.0-M5</version>
    <configuration>
        <forkCount>1</forkCount>
        <reuseForks>false</reuseForks>
    </configuration>
</plugin>

junkdog on Dec 8, 2020

Since mocking method causes an issue one approach to avoid it is to use reflection to get the real method instead. e.g.

final var method = IdentifiableEntity.class.getDeclaredMethod("getId");

trajano on Aug 10, 2023

I’ll try to do one next week, after I return from vacation, but, in the meantime, I’ve commented out tests one-by-one, until I discovered what triggers the problem…

One of them has a Mockito.mock(Method.class). The test itself, ran by itself, works… but if the whole suite is ran, some tests that follow it get the problem described above.

Removing the mocking of the java.lang.reflect.Method made everything green again.

andrei-ivanov on Sep 4, 2020