unable to use JMock after updating to Java 17

Question

I'm updating our large old java desktop application from Java 11 to java 17. I've updated all the jars to the latest versions. jmock-2.12.0, cglib-3.3.0, asm-9.4. Working with JUnit 4 tests. A LOT of our JUnit tests are failing with a:

java.lang.reflect.InaccessibleObjectException: Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @5ce81285

Full stack trace:

java.lang.ExceptionInInitializerError
    at org.jmock.lib.legacy.ClassImposteriser.proxyClass(ClassImposteriser.java:100)
    at org.jmock.lib.legacy.ClassImposteriser.imposterise(ClassImposteriser.java:69)
    at org.jmock.Mockery.mock(Mockery.java:167)
    at com.metrixsoftware.servicebroker.MetrixTestCase.mock(MetrixTestCase.java:95)
    at com.metrixsoftware.api.mis.Test_DiecutterToolEdit.setupMetrixMISManager(Test_DiecutterToolEdit.java:125)
    at com.metrixsoftware.api.mis.Test_DiecutterToolEdit.setup(Test_DiecutterToolEdit.java:59)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:568)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
    at org.junit.internal.runners.statements.RunBefores.invokeMethod(RunBefores.java:33)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
    at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
    at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:54)
    at org.junit.rules.RunRules.evaluate(RunRules.java:20)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:93)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:40)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:529)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:756)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:452)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)
Caused by: net.sf.cglib.core.CodeGenerationException: java.lang.reflect.InaccessibleObjectException-->Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @5ce81285
    at net.sf.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:464)
    at net.sf.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:339)
    at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:96)
    at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:94)
    at net.sf.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at net.sf.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61)
    at net.sf.cglib.core.internal.LoadingCache.get(LoadingCache.java:34)
    at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:119)
    at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:294)
    at net.sf.cglib.core.KeyFactory$Generator.create(KeyFactory.java:221)
    at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:174)
    at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:153)
    at net.sf.cglib.proxy.Enhancer.<clinit>(Enhancer.java:73)
    ... 38 more
Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @5ce81285
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:354)
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297)
    at java.base/java.lang.reflect.Method.checkCanSetAccessible(Method.java:199)
    at java.base/java.lang.reflect.Method.setAccessible(Method.java:193)
    at net.sf.cglib.core.ReflectUtils$1.run(ReflectUtils.java:61)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:569)
    at net.sf.cglib.core.ReflectUtils.<clinit>(ReflectUtils.java:52)
    at net.sf.cglib.core.KeyFactory$Generator.generateClass(KeyFactory.java:243)
    at net.sf.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:25)
    at net.sf.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:332)
    ... 50 more

Is there any way to get our calls to Mockery.mock(class,name) to work?

Looking at the stack trace the issue is `cglib` which seems to be used by jmock? The [cglib repo](https://github.com/cglib/cglib) also has this note: `IMPORTANT NOTE: cglib is unmaintained and does not work well (or possibly at all?) in newer JDKs, particularly JDK17+`. Though, it seems like jmock can also use ByteBuddy (I think). So, you might be able to solve this be switching to ByteBuddy from cglib. — Jorn Vernee, Dec 08 '22 at 22:02
I had found a few comments that jmock(it,or other variation) could use ByteBuddy. I don't see HOW Jmock can use it, as it references cglib classes directly. I also was a bit confused, as I was searching on Maven Central for "ByteBuddy" - and finally figured out I needed to search for "Byte-Buddy". A quick test shows that JMock is definitely using cglib classes, and not ByteBuddy ones. — CasaDelGato, Dec 08 '22 at 22:17
Jmock seems to support different 'imposterisers'. There's also one for ByteBuddey: https://github.com/jmock-developers/jmock-library/blob/master/jmock-imposters/src/main/java/org/jmock/imposters/ByteBuddyClassImposteriser.java It seems from your stack trace that the legacy cglib-based imposteriser is being used. It also seems that the imposteriser can be set through [`Mockery.setImposteriser`](https://github.com/jmock-developers/jmock-library/blob/307f6c213ce21054c55d49311f01fb22dfc65fd2/jmock/src/main/java/org/jmock/Mockery.java#L86). So I think that's what you'll have to do. — Jorn Vernee, Dec 08 '22 at 22:27
Looking good. After some digging around, I added "jmock-imposters-2.12.0.jar" and "byte-buddy-1.12.19.jar". Deleted cglib. Hmm, probably should delete asm as well. Also changed calls to setImposteriser() to setImposteriser(ByteBuddyClassImposteriser.INSTANCE); Running a test now. — CasaDelGato, Dec 08 '22 at 23:23

score 2 · Answer 1 · answered Dec 09 '22 at 17:05

2

Thanks to Jorn Vernee for pointing me in the correct direction. The fix was to: Delete the cglib jar and asm jar files. Add "jmock-imposters-2.12.0.jar" and "byte-buddy-1.12.19.jar". Now JMock is working.

answered Dec 09 '22 at 17:05

CasaDelGato

603
7
17

unable to use JMock after updating to Java 17

1 Answers1