PowerMockito: java.lang.NoClassDefFoundError

Question

I need to mock a static final class in my Junit test:

private MyFinalClient client;

@Before
public void setup() {

    // set up mock
    client = PowerMockito.mock(MyFinalClient.class);
    service = new PatientLocationService();
    service.setClient(client);
}

When I run the test I will get the following error message:

java.lang.NoClassDefFoundError: Could not initialize class MyFinalClient$$EnhancerByMockitoWithCGLIB$$7bb8ec03
at sun.reflect.GeneratedSerializationConstructorAccessor6.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at org.objenesis.instantiator.sun.SunReflectionFactoryInstantiator.newInstance(SunReflectionFactoryInstantiator.java:45)
at org.objenesis.ObjenesisBase.newInstance(ObjenesisBase.java:73)
at org.mockito.internal.creation.instance.ObjenesisInstantiator.newInstance(ObjenesisInstantiator.java:14)
at org.powermock.api.mockito.repackaged.ClassImposterizer.createProxy(ClassImposterizer.java:143)
at org.powermock.api.mockito.repackaged.ClassImposterizer.imposterise(ClassImposterizer.java:58)
at org.powermock.api.mockito.internal.mockcreation.MockCreator.createMethodInvocationControl(MockCreator.java:110)
at org.powermock.api.mockito.internal.mockcreation.MockCreator.mock(MockCreator.java:58)
at org.powermock.api.mockito.PowerMockito.mock(PowerMockito.java:143)
at com.hihi.ohyeahServiceTest.setup(ohyeahServiceTest.java:53)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at org.junit.internal.runners.MethodRoadie.runBefores(MethodRoadie.java:132)
at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:95)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:294)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:127)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:82)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:282)
at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:86)
at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:49)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:207)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:146)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:120)
at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:33)
at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:45)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:122)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:106)
at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:53)
at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:78)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:212)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)

Not entirely sure why I am getting this... This will not generate any error if I do this in Spring Tool Suite but will break on command prompt and in IntelliJ (in normal eclipse as well)

Please help!

Thanks!

edit: Here is the powermock info:

<dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-api-mockito</artifactId>
        <version>1.6.2</version>
        <scope>test</scope>
    </dependency>

I am using spring boot starter test and from class path i can see i am using:

• mockito-all-1.9.5
• mockito-core-1.10.19

I imported the project via import->existing Maven project (by including the pom.xml) where in Idea I am doing similar things as well...

Answer 1

I think you might be missing some bootstrapping of your test class. Do you have annotations on your test case class like this?

@RunWith(PowerMockRunner.class)
@PrepareForTest(MyFinalClient.class)

That'll get powermock to prepare the MyFinalClient class with some bytecode manipulation so that it can properly generate the mock.

I've also noticed some weirdness under JVM 8 when doing things like this where the byte code verifier will complain when your test runs. You can get around that by adding the '-noverify' flag to your jvmargs at test.