jMockit Error on Initialization: java.lang.IllegalStateException: Running on JDK 9

4
votes

jmockit cannot initialize in eclipse: java.lang.IllegalStateException: Running on JDK 9 requires -javaagent:/jmockit-1.n.jar or -Djdk.attach.allowAttachSelf

If I add the -Djdk.attach.allowAttachSelf VM argument, it works fine.

Why would I need to add that argument? jmockit doesn't say that is required when running on JDK 9. Yes, the JRE System library points to JDK, and yes the jmockit jar is above junit in the order of external libraries.

Versions: JUnit 4.12, Java jdk 9.0.1, jmockit 1.37, hamcrest core 1.3

java.lang.ExceptionInInitializerError at testClass.testMethod(testClass.java:20) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:564) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) 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:539) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:761) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:461) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:207) Caused by: java.lang.IllegalStateException: Running on JDK 9 requires -javaagent:/jmockit-1.n.jar or -Djdk.attach.allowAttachSelf at mockit.internal.startup.AgentLoader.attachToRunningVM(AgentLoader.java:155) at mockit.internal.startup.AgentLoader.loadAgent(AgentLoader.java:60) at mockit.internal.startup.Startup.verifyInitialization(Startup.java:137) at mockit.Invocations.(Invocations.java:26) ... 24 more

1
javaeclipsejunitjava-9jmockit
Note that JMockit does say it is required (well, that or using -javaagent) on JDK 9, in the exception message! Better than documentation, which most people never read... – Rogério
@Rogerio, ha, i always do get in trouble for reading documentation... – user2706641

1 Answers

5
votes

-Djdk.attach.allowAttachSelf vm argument, it works fine.

Why would I need to add that argument?

The argument in JDK9 is used to attach to the local VM itself in other words for self-attach.

jmockit mostly uses a self-attach for Instrumentation and that is where they would be requiring such a flag. Also, this must argument shall be ignored on JDK8 or previous.

An initial discussion over the same could be found on jigsaw mailing list.

A similar discussion and a workaround was proposed at byte-buddy#295 by @Rafael :-

ByteBuddyAgent.install() does now detect Java 9 VMs where self-attachment is forbidden and creates a helper process to attach from there.