Byteman agent fails to load on the IBM J9 VM

[mmusgrov]

We use BMUnitRunner test annotation to dynamically load the agent into the IBM J9 VM which fails with

*** java.lang.instrument ASSERTION FAILED ***: "jvmtierror == JVMTI_ERROR_NOT_AVAILABLE" at JPLISAgent.c line: 1009

Exception in thread "Attachment 59984" Agent failed to start!

JVMJ9TI064E Agent initialization function Agent_OnAttach failed for library instrument, return code 102

We have raised issue [JBTM-2440] Byteman tests fail when running with the IBM JVM - JBoss Issue Tracker to track the problem.

Is this something that bytman could support, in which case I will raise a byteman issue, or alternatively is there a workaround?

[adinn]

Hi Mike,

Is this something that bytman could support?

I think you will have to ask the IBM J9 team about that or -- if you are really desperate -- read the J9 manual.

Byteman relies upon the underlying host JVM/JDK to support the Java agent Attach API. The error message suggests that -- at least with the default configuration -- J9 does not support this API. It may be that J9 does support it but disables it by default. I don't really know the answer to that.

Ok, I looked online and the IBM docs appears to suggest that Java agents are supported from the command line. It also looks like they may require a property setting for dynamic loading using the Attach API. Did this work using the J9 JDK7 release? If so then this may represent a change from enabling agents by default to disabling them by default. If that is correct you could try running with this define on the command line

-Dcom.ibm.tools.attach.enable=yes

The JDK8 docs offer this setting as a way of enabling agent loads to proceed.