On AIX using zlibNX may cause ClassNotFoundException

[pshipton]

Experienced the following problem on AIX 7.3 P10, which is configured to support zlibNX, and Semeru will use it be default. Disable using -XX:-UseZlibNX and it no longer occurs.

00:52:14  /home/jenkins/workspace/Test_openjdk23_j9_sanity.jck_ppc64_aix/jdkbinary/j2sdk-image/bin/java -cp ./bin/TestKitGen.jar org.openj9.envInfo.EnvDetector
00:52:14  Exception in thread "main" java.lang.NoClassDefFoundError: org.openj9.envInfo.MachineInfo
00:52:14  	at org.openj9.envInfo.EnvDetector.parseArgs(EnvDetector.java:32)
00:52:14  	at org.openj9.envInfo.EnvDetector.main(EnvDetector.java:28)
00:52:14  Caused by: java.lang.ClassNotFoundException: org.openj9.envInfo.MachineInfo
00:52:14  	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:827)
00:52:14  	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
00:52:14  	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:1099)
00:52:14  	... 2 more

Trying to look at the class with javap you get unexpected end of file while reading org.openj9.envInfo.MachineInfo.

jdk11, 17 seem fine, this particular problem only occurs with jdk21, 23. However we don't know how the bug might affect earlier versions.

[github-actions]

Issue Number: 20324
Status: Open
Recommended Components: comp:test, comp:vm, comp:build
Recommended Assignees: keithc-ca, pshipton, jasonfengj9

[pshipton]

There is an AIX ifix related to case TS017146010 which is supposed to fix it. Until the fix is part of a service pack or TL, disable zlibNX by default. The command line option can still be used to enable it, when using the default java launcher.

ibmruntimes/openj9-openjdk-jdk#858
ibmruntimes/openj9-openjdk-jdk23#55
ibmruntimes/openj9-openjdk-jdk21#209
ibmruntimes/openj9-openjdk-jdk17#396
ibmruntimes/openj9-openjdk-jdk11#823
ibmruntimes/openj9-openjdk-jdk8#768

Created doc issue
eclipse-openj9/openj9-docs#1426

[pshipton]

Although the default has been changed, we can keep this open until there is an AIX update with the fix and the default to enable zlibNX restored.

[paulcheeseman]

This is the AIX APAR:

https://www.ibm.com/support/docview.wss?uid=isg1IJ52189

I believe the fix is available.

EDIT: Actually I think the fix is available as an AIX iFix only - i.e. not in an official AIX release yet.

[pshipton]

The link I have to the AIX ifix for case TS017146010 shows it's expired.
Apparently any AIX ifix is specific to the target system.