How to resolve the following error related to powermockito: "Mockito cannot mock this class: class org.apache.hadoop.fs.FileSystem."

Question

This is the entire error:

Mockito cannot mock this class: class org.apache.hadoop.fs.FileSystem.

Mockito can only mock non-private & non-final classes.
If you're not sure why you're getting this error, please report to the mailing list.


Java               : 1.8
JVM vendor name    : Azul Systems, Inc.
JVM vendor version : 25.282-b08
JVM name           : OpenJDK 64-Bit Server VM
JVM version        : 1.8.0_282-b08
JVM info           : mixed mode
OS name            : Mac OS X
OS version         : 10.16


Underlying exception : java.lang.IllegalStateException: Error invoking java.lang.reflect.Method#getAnnotatedReturnType
org.mockito.exceptions.base.MockitoException: 
Mockito cannot mock this class: class org.apache.hadoop.fs.FileSystem.

Mockito can only mock non-private & non-final classes.
If you're not sure why you're getting this error, please report to the mailing list.


Java               : 1.8
JVM vendor name    : Azul Systems, Inc.
JVM vendor version : 25.282-b08
JVM name           : OpenJDK 64-Bit Server VM
JVM version        : 1.8.0_282-b08
JVM info           : mixed mode
OS name            : Mac OS X
OS version         : 10.16


Underlying exception : java.lang.IllegalStateException: Error invoking java.lang.reflect.Method#getAnnotatedReturnType
    at com.platfora.proton.builder.spark.TestCredentialManager.initTest(TestCredentialManager.java:109)
    at org.junit.internal.runners.MethodRoadie.runBefores(MethodRoadie.java:133)
    at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:96)
    at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:87)
    at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:50)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
    at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:118)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
    at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:412)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalStateException: Error invoking java.lang.reflect.Method#getAnnotatedReturnType
    at net.bytebuddy.description.type.TypeDescription$Generic$AnnotationReader$Dispatcher$ForJava8CapableVm$AnnotatedReturnType.resolve(TypeDescription.java:2984)
    at net.bytebuddy.description.type.TypeDescription$Generic$AnnotationReader$Delegator.asList(TypeDescription.java:3238)
    at net.bytebuddy.description.type.TypeDescription$Generic$OfNonGenericType$ForLoadedType.getDeclaredAnnotations(TypeDescription.java:3987)
    at net.bytebuddy.implementation.attribute.AnnotationAppender$ForTypeAnnotations.apply(AnnotationAppender.java:725)
    at net.bytebuddy.implementation.attribute.AnnotationAppender$ForTypeAnnotations.onNonGenericType(AnnotationAppender.java:706)
    at net.bytebuddy.implementation.attribute.AnnotationAppender$ForTypeAnnotations.onNonGenericType(AnnotationAppender.java:409)
    at net.bytebuddy.description.type.TypeDescription$Generic$OfNonGenericType.accept(TypeDescription.java:3769)
    at net.bytebuddy.implementation.attribute.MethodAttributeAppender$ForInstrumentedMethod.apply(MethodAttributeAppender.java:196)
    at net.bytebuddy.implementation.attribute.MethodAttributeAppender$Compound.apply(MethodAttributeAppender.java:484)
    at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod$WithBody.applyAttributes(TypeWriter.java:701)
    at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod$WithBody.applyBody(TypeWriter.java:691)
    at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod.apply(TypeWriter.java:600)
    at net.bytebuddy.dynamic.scaffold.TypeWriter$Default$ForCreation.create(TypeWriter.java:5660)
    at net.bytebuddy.dynamic.scaffold.TypeWriter$Default.make(TypeWriter.java:2166)
    at net.bytebuddy.dynamic.scaffold.subclass.SubclassDynamicTypeBuilder.make(SubclassDynamicTypeBuilder.java:232)
    at net.bytebuddy.dynamic.scaffold.subclass.SubclassDynamicTypeBuilder.make(SubclassDynamicTypeBuilder.java:204)
    at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase.make(DynamicType.java:3595)
    at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase$Delegator.make(DynamicType.java:3819)
    at org.mockito.internal.creation.bytebuddy.SubclassBytecodeGenerator.mockClass(SubclassBytecodeGenerator.java:173)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator$1.call(TypeCachingBytecodeGenerator.java:37)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator$1.call(TypeCachingBytecodeGenerator.java:34)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:152)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:365)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:174)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:376)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.mockClass(TypeCachingBytecodeGenerator.java:32)
    at org.mockito.internal.creation.bytebuddy.SubclassByteBuddyMockMaker.createMockType(SubclassByteBuddyMockMaker.java:71)
    at org.mockito.internal.creation.bytebuddy.SubclassByteBuddyMockMaker.createMock(SubclassByteBuddyMockMaker.java:42)
    at org.mockito.internal.creation.bytebuddy.ByteBuddyMockMaker.createMock(ByteBuddyMockMaker.java:25)
    at org.powermock.api.mockito.mockmaker.PowerMockMaker.createMock(PowerMockMaker.java:41)
    at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:35)
    at org.mockito.internal.MockitoCore.mock(MockitoCore.java:63)
    at org.mockito.Mockito.mock(Mockito.java:1908)
    at org.powermock.api.mockito.internal.mockcreation.DefaultMockCreator.createMethodInvocationControl(DefaultMockCreator.java:108)
    at org.powermock.api.mockito.internal.mockcreation.DefaultMockCreator.doCreateMock(DefaultMockCreator.java:61)
    at org.powermock.api.mockito.internal.mockcreation.DefaultMockCreator.createMock(DefaultMockCreator.java:53)
    at org.powermock.api.mockito.internal.mockcreation.DefaultMockCreator.mock(DefaultMockCreator.java:40)
    at org.powermock.api.mockito.PowerMockito.mock(PowerMockito.java:126)
    at com.platfora.proton.builder.spark.TestCredentialManager.initTest(TestCredentialManager.java:109)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.internal.runners.MethodRoadie.runBefores(MethodRoadie.java:133)
    at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:96)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:310)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:131)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.access$100(PowerMockJUnit47RunnerDelegateImpl.java:59)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner$TestExecutorStatement.evaluate(PowerMockJUnit47RunnerDelegateImpl.java:147)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.evaluateStatement(PowerMockJUnit47RunnerDelegateImpl.java:107)
    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:298)
    at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:87)
    at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:50)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:218)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:160)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:134)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:136)
    at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:117)
    at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:57)
    at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
    at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:118)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    ... 11 more
Caused by: java.lang.IllegalStateException: Failed to transform class with name org.apache.hadoop.fs.FileSystem$Cache. Reason: org.apache.hadoop.fs.FileSystem$Cache$Key class is frozen
    at org.powermock.core.classloader.javassist.JavassistMockClassLoader.defineAndTransformClass(JavassistMockClassLoader.java:119)
    at org.powermock.core.classloader.MockClassLoader.loadMockClass(MockClassLoader.java:174)
    at org.powermock.core.classloader.MockClassLoader.loadClassByThisClassLoader(MockClassLoader.java:102)
    at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass1(DeferSupportingClassLoader.java:147)
    at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:98)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:352)
    at java.lang.Class.getDeclaringClass0(Native Method)
    at java.lang.Class.getDeclaringClass(Class.java:1235)
    at java.lang.Class.getEnclosingClass(Class.java:1277)
    at sun.reflect.annotation.AnnotatedTypeFactory.addNesting(AnnotatedTypeFactory.java:96)
    at sun.reflect.annotation.AnnotatedTypeFactory.buildAnnotatedType(AnnotatedTypeFactory.java:65)
    at sun.reflect.annotation.TypeAnnotationParser.buildAnnotatedType(TypeAnnotationParser.java:79)
    at java.lang.reflect.Executable.getAnnotatedReturnType0(Executable.java:640)
    at java.lang.reflect.Method.getAnnotatedReturnType(Method.java:648)
    at sun.reflect.GeneratedMethodAccessor19.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at net.bytebuddy.description.type.TypeDescription$Generic$AnnotationReader$Dispatcher$ForJava8CapableVm$AnnotatedReturnType.resolve(TypeDescription.java:2980)
    ... 92 more
Caused by: java.lang.RuntimeException: org.apache.hadoop.fs.FileSystem$Cache$Key class is frozen
    at javassist.CtClassType.checkModify(CtClassType.java:334)
    at javassist.CtBehavior.setModifiers(CtBehavior.java:178)
    at org.powermock.core.transformers.javassist.ConstructorsMockTransformer.transform(ConstructorsMockTransformer.java:64)
    at org.powermock.core.transformers.javassist.ConstructorsMockTransformer.transform(ConstructorsMockTransformer.java:51)
    at org.powermock.core.transformers.javassist.AbstractJavaAssistMockTransformer.transform(AbstractJavaAssistMockTransformer.java:40)
    at org.powermock.core.transformers.support.DefaultMockTransformerChain.transform(DefaultMockTransformerChain.java:43)
    at org.powermock.core.classloader.MockClassLoader.transformClass(MockClassLoader.java:184)
    at org.powermock.core.classloader.javassist.JavassistMockClassLoader.defineAndTransformClass(JavassistMockClassLoader.java:102)
    ... 109 more

This seems to be related to us upgrading our log4j version. The test works fine in a branch with the log4j version being 1.2.17. The current version is 2.16.0. We must keep the log4j version at 2.16 – we updated it to remove a security vulnerability.

This is the Apache Hadoop FileSystem class:

@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class FileSystem extends Configured
    implements Closeable, DelegationTokenIssuer {
  public static final String FS_DEFAULT_NAME_KEY =
                   CommonConfigurationKeys.FS_DEFAULT_NAME_KEY;
  public static final String DEFAULT_FS =
                   CommonConfigurationKeys.FS_DEFAULT_NAME_DEFAULT;

  /**
   * This log is widely used in the org.apache.hadoop.fs code and tests,
   * so must be considered something to only be changed with care.
   */
  @InterfaceAudience.Private
  public static final Log LOG = LogFactory.getLog(FileSystem.class);

  /**
   * The SLF4J logger to use in logging within the FileSystem class itself.
   */
  private static final Logger LOGGER =
      LoggerFactory.getLogger(FileSystem.class);

As you can see on the bottom line above, we initialize the logger.

This is the test class that is failing:

@PrepareForTest({ UserGroupInformation.class, CredentialManager.class, KerberosUtil.class, FileSystem.class,
    HadoopBDSConfigurator.class })
@RunWith(PowerMockRunner.class)
@PowerMockIgnore({ "javax.management.*", "javax.security.*"})
@ProtonTestType(ProtonTestCategory.SYSTEM_INTEGRATION)
@ProtonTestTags(tags = {ProtonTestTag.DSS})
public class TestCredentialManager {

    private static final String realm = "TEST.REALM";
    private static final String tenantUser = "testTenantUser";
    private static final String tenantUserWithRealm = tenantUser+"@"+realm;
    private static final String TOKEN_ALIAS = "token_alias";
    private static final String TOKEN_ALIAS_2 = "token_alias_2";
    private static final byte[] expected = {72, 68, 84, 83, 0, 1, 11, 116, 111, 107, 101, 110, 95, 97, 108, 105, 97, 115, 0, 0, 0, 0, 0};
//    private static FileSystemTestHelper.MockFileSystem mockFileSystem;
    private static FileSystem mockFileSystem;

    final Logger logger = LoggerFactory.getLogger(TestCredentialManager.class);

    @BeforeClass
    public static void init()
            throws Exception {
        ProtonBootstrap.initForUnitTests();
        PlatforaConfig.SPARK_QUERY_TOKEN_FETCH_REPEATS.setup(null,System.getProperties());
        if (PrismToggles.toggleRenewDelegationToken().isEnabled()) {
            CredentialManager.getInstance().prismDTCache().clear();
        } else {
            CredentialManager.getInstance().tokenExpiryCache().clear();
        }
        CredentialManager.getInstance().tenantCredentialsCache().clear();
    }

    @Before
    public void initTest()
            throws Exception {
        mockFileSystem = PowerMockito.mock(FileSystem.class);
        PowerMockito.mockStatic(FileSystem.class);
        doReturn(this.mockFileSystem).when(FileSystem.class, "get", any());
    }

    @After
    public void reset() {
        if (PrismToggles.toggleRenewDelegationToken().isEnabled()) {
            CredentialManager.getInstance().prismDTCache().clear();
        } else {
            CredentialManager.getInstance().tokenExpiryCache().clear();
        }
        CredentialManager.getInstance().tenantCredentialsCache().clear();
    }
    @Test
    public void testSerializeCredentials() {
        final Credentials credentials = getCredentialsWithToken();
        final ByteArray byteArray = CredentialManager.getInstance().serializeCredentials(credentials);
        Assert.assertArrayEquals(expected, byteArray.bytes);
    }

It is specifically failing on this line mockFileSystem = PowerMockito.mock(FileSystem.class);

Mockito version: 2.8.9 Powermock version:2.0.9

I have tried the following things:

• Going to the project structure and making sure that the versions of mockito and powermockito were consistent. Found a conflict with both two mockitos being there: 2.8.9 and 3.3.3. Tried to remove the newer one and it didn't resolve the issue.
• In project structure, there are 5 javassist packages with an 'org' prefix and one without. Tried these options: 1) removing the non-org package 2) only the org 3.18 package 3) only the lastest org package 4) steps 2 and 3 with the other non-org package present
• Tried to move the mock(FileSystem.class) and mockStatic(...) lines in a static code block at the beginning of the class definition before the log instantiation. We thought this might help if it happens before the log4j stuff, but same issue.
• Apache actually has a class called MockFileSystem with is a subclass of FileSystem. I tried to replace this in the code directly, but we still have the same issue, probably because it still has to initilize log4j in the superclass in the same manner. So still same issue despite MockFileSystem not being abstract

I have scavenged the web and am running out of ideas. Can someone help? It seems to be related to the log4j logger being instantiated in the FileSystem class and it not being compatible with that Powermock instantiation.