Getting javassist.NotFoundException with PowerMock and PowerRule in JUnit with Mockito

I have integrated PowerMock and PowerRule in JUnit with Mockito.

Here are my dependencies:

<dependency>
        <groupId>javassist</groupId>
        <artifactId>javassist</artifactId>
        <version>3.12.0.GA</version>
      </dependency>
<dependency>
        <groupId>asm</groupId>
        <artifactId>asm</artifactId>
        <version>3.3.1</version>
</dependency>

 <dependency>
        <groupId>cglib</groupId>
        <artifactId>cglib</artifactId>
        <version>2.2.2</version>
 </dependency>
 <dependency>
        <groupId>org.powermoc</groupId>
    <artifactId>powermock-module-junit4</artifactId>
    <version>1.4.12</version>
    <scope>test</scope>
    </dependency>
 <dependency>
    <groupId>org.powermock</groupId>
    <artifactId>powermock-api-mockito</artifactId>
    <version>1.4.12</version>
    <scope>test</scope>
 </dependency>
 <dependency>
       <groupId>org.powermock</groupId>
       <artifactId>powermock-module-junit4-rule</artifactId>
       <version>1.4.12</version>
       <scope>test</scope>
 </dependency>
 <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-classloading-objenesis</artifactId>
        <version>1.4.12</version>
        <scope>test</scope>
 </dependency>

My test class is:

public class TestClass extends AbstractShiroTest{
    @Rule
    public PowerMockRule rule = new PowerMockRule();
    @Autowired
    SomeService someService;
    @Before

    public void setUp(){
    Map<String, Object> newMap = new HashMap<String, Object>();
    newMap.put("userTimeZone", "Asia/Calcutta");
    Subject subjectUnderTest = mock(Subject.class);
             when(subjectUnderTest.getPrincipal()).thenReturn(LMPTestConstants.USER_NAME);
    Session session = mock(Session.class);
    when(session.getAttribute(LMPCoreConstants.USER_DETAILS_MAP)).thenReturn(newMap);
    when(subjectUnderTest.getSession(false)).thenReturn(session);
    setSubject(subjectUnderTest);
    PowerMockito.mockStatic(CasSessionUtil.class);
    when(CasSessionUtil.getCarrierId()).thenReturn(1L);
}

  @Test

public void myTestMethod()  {
someService.doSomething();
 }
}

doSomething is calling a static method that I need to mock. When I run my test case, I get javassist.NotFoundException: $Proxy88.

Full stack trace:

java.lang.RuntimeException: javassist.NotFoundException: $Proxy88 at org.powermock.core.classloader.MockClassLoader.loadUnmockedClass(MockClassLoader.java:187) at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:147) at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:67) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:247) at org.powermock.api.support.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:66) at org.powermock.api.support.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:26) at org.powermock.classloading.DeepCloner.cloneFields(DeepCloner.java:243) at org.powermock.classloading.DeepCloner.performClone(DeepCloner.java:128) at org.powermock.classloading.DeepCloner.cloneFields(DeepCloner.java:248) at org.powermock.classloading.DeepCloner.performClone(DeepCloner.java:128) at org.powermock.classloading.DeepCloner.cloneFields(DeepCloner.java:248) at org.powermock.classloading.DeepCloner.performClone(DeepCloner.java:128) at org.powermock.classloading.DeepCloner.cloneFields(DeepCloner.java:248) at org.powermock.classloading.DeepCloner.performClone(DeepCloner.java:128) at org.powermock.classloading.DeepCloner.cloneFields(DeepCloner.java:248) at org.powermock.classloading.DeepCloner.performClone(DeepCloner.java:128) at org.powermock.classloading.DeepCloner.cloneFields(DeepCloner.java:248) at org.powermock.classloading.DeepCloner.performClone(DeepCloner.java:128) at org.powermock.classloading.DeepCloner.cloneFields(DeepCloner.java:248) at org.powermock.classloading.DeepCloner.performClone(DeepCloner.java:128) at org.powermock.classloading.DeepCloner.clone(DeepCloner.java:82) at org.powermock.classloading.DeepCloner.clone(DeepCloner.java:69) at org.powermock.classloading.ClassloaderExecutor.execute(ClassloaderExecutor.java:89) at org.powermock.classloading.ClassloaderExecutor.execute(ClassloaderExecutor.java:78) at org.powermock.modules.junit4.rule.PowerMockStatement.evaluate(PowerMockRule.java:49) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Caused by: javassist.NotFoundException: $Proxy88 at javassist.ClassPool.get(ClassPool.java:436) at org.powermock.core.classloader.MockClassLoader.loadUnmockedClass(MockClassLoader.java:180) ... 46 more

If I change the dependency to

<dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-classloading-xstream</artifactId>
            <version>1.4.12</version>
            <scope>test</scope>
        </dependency>

then I get a different exception. Please see https://stackoverflow.com/questions/12176049/suggest-work-around-for-com-thoughtworks-xstream-converters-conversionexception (deleted SO question, requires 10k).

I have even tried with javassist version 15, but that has the same problem.

Answers


Found out the solution myself:

Use the below dependencies (for Power Mock and Power Rule) only

    <!-- Required for PowerMock -->
    <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-api-mockito</artifactId>
        <version>1.4.12</version>
        <scope>test</scope>
    </dependency>
    <!-- Required for PowerMockRule -->
    <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-module-junit4-rule-agent</artifactId>
        <version>1.4.12</version>
        <scope>test</scope>
    </dependency>

Now I am not getting either of the above exceptions


Replace powermock-module-junit4-rule with powermock-module-junit4-rule-agent.

<dependency>
    <groupId>org.powermock</groupId>
    <artifactId>powermock-module-junit4-rule-agent</artifactId>
    <scope>test</scope>
</dependency>

The main difference between the agent based bootstrapper and the classloading based bootstrapper is that you don't run into classloading issues.


Without more code samples I gather that the code is using Spring in the test. So I believe the reason for this error is that related to Spring use, which do seem to have generated JDK proxies (the $Proxy88).

And the way Powermock is working is by running the JUnit test in a new classloader in order to modify the bytecode of these classes, unfortunately it is only possible to modify the bytecode from a the real file, or at least from a location where it's possible to read the class binary, as java cannot access bytecode already loaded in the JVM. (It may be possible with an agent in a limited way).

As JDK proxies do not exists on disk, they cannot be read, or copied to the specific Powermock classloader.

The test you are writing is not a unit test as it is run with a Spring context. You might want to write a real Unit Test first. Then some Integration Test, in which you won't need mocks.

Also you should avoid the use of statics, as it is a testability nightmare. You should rewrite your production code in a way where static calls don't need to be mocked.

Cheers,


@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:/test-servlet.xml")
public class ControlCenterManagerImplTest {

@Rule
public  PowerMockRule rule = new PowerMockRule();

//Powermock agent initialization not required and using maven dependency specified above by BHUVAN we can execute Power mock using spring.}

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