Junit Mockito error on initialization

Question

I have looked everywhere online. I have tried almost everything, from deleting STS to deleting all the code from my station and re-import everything back. I played with dependencies, build path, properties, etc. but still nothing works.

Running the tests on Maven by CLI is working fine, and other team members don't have that issue, so it is probably some configuration on my station.

The problem:

When I try to debug/run a unit test inside STS using JUnit v. 4 I get an error with the following stack trace:

java.lang.IllegalAccessError: class org.mockito.internal.creation.jmock.ClassImposterizer$1 cannot access its superclass org.mockito.internal.creation.cglib.MockitoNamingPolicy
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.mockito.internal.creation.jmock.ClassImposterizer.<clinit>(ClassImposterizer.java:38)
at org.mockito.internal.creation.CglibMockMaker.createMock(CglibMockMaker.java:23)
at org.powermock.api.mockito.internal.mockmaker.PowerMockMaker.createMock(PowerMockMaker.java:43)
at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:33)
at org.mockito.internal.MockitoCore.mock(MockitoCore.java:59)
at org.mockito.Mockito.mock(Mockito.java:1285)
at org.mockito.internal.configuration.MockAnnotationProcessor.process(MockAnnotationProcessor.java:33)
at org.mockito.internal.configuration.MockAnnotationProcessor.process(MockAnnotationProcessor.java:16)
at org.mockito.internal.configuration.DefaultAnnotationEngine.createMockFor(DefaultAnnotationEngine.java:43)
at org.mockito.internal.configuration.DefaultAnnotationEngine.process(DefaultAnnotationEngine.java:66)
at org.mockito.internal.configuration.InjectingAnnotationEngine.processIndependentAnnotations(InjectingAnnotationEngine.java:71)
at org.mockito.internal.configuration.InjectingAnnotationEngine.process(InjectingAnnotationEngine.java:55)
at org.mockito.MockitoAnnotations.initMocks(MockitoAnnotations.java:108)
at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl$1.withBefores(JUnit45AndHigherRunnerImpl.java:27)
at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:254)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

If anyone have any idea on what the problem might be...

Here is part of the POM:

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.4.2.RELEASE</version>
    <relativePath>org.springframework.boot:spring-boot-starter-parent</relativePath>
</parent>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
    </dependency>
    <dependency>
        <groupId>com.mockrunner</groupId>
        <artifactId>mockrunner</artifactId>
        <version>0.3.1</version>
    </dependency>

Answer 1

spring-boot-starter-test 1.4.2.RELEASE uses Mockito 1.10.19 by default, org.mockito.internal.creation.jmock.ClassImposterizer doesn't exist in 1.10.19. It's now in the org.mockito.internal.creation.cglib package.

Exclude org.mockito from spring-boot-starter-test, as follows:

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.mockito</groupId>
                    <artifactId>mockito-core</artifactId>
                </exclusion>
            </exclusions>
</dependency>

And include mockito-all 1.9.5 as a dependency:

<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-core</artifactId>
    <version>1.9.5</version>
    <scope>test</scope>
</dependency>

Answer 2

This happens when there are multiple versions of mockito. Exclude mockito version which is being transitively brought by other dependencies.

<exclusion>
 <artifactId>mockito-all</artifactId>
 <groupId>org.mockito</groupId>
 </exclusion>

This worked in my case.