[slf4j-dev] SLF4J 1.8 on JVMs < 9

18 Feb 2019

      Hi,

I just joined this list, so first hi from Germany ;-)

When I use slf4j-1.8.0-beta2 in an application that is being deployed to 
our Websphere 9 server, I see error messages in the deployment manager 
console:

(...)
[2/18/19 15:51:31:862 CET] 000022bd WSModuleDescr E   WSWS7011E: The 
configuration for the myapp-war-2019.4.0-SNAPSHOT.war application module 
cannot load correctly.
The following error occurred: 
com.ibm.ws.metadata.annotations.AnnotationException: Annotation processing 
failed for class:  module-info.class
        at 
com.ibm.ws.metadata.annotations.AnnotationConfigReader.getAnnotationData(AnnotationConfigReader.java:883)
        at 
com.ibm.ws.metadata.annotations.AnnotationConfigReader.getAnnotationDataForZippedArchive(AnnotationConfigReader.java:766)
        at 
com.ibm.ws.metadata.annotations.AnnotationConfigReader.getAnnotationData(AnnotationConfigReader.java:696)
        at 
com.ibm.ws.metadata.annotations.AnnotationConfigReader.populateModuleData(AnnotationConfigReader.java:353)
        at 
com.ibm.ws.metadata.MetaDataOrchestrator.getModuleData(MetaDataOrchestrator.java:112)
        at 
com.ibm.ws.websvcs.annotations.collector.WASAnnotationCollector.getMDO(WASAnnotationCollector.java:258)
        at 
com.ibm.ws.websvcs.annotations.collector.WASAnnotationCollector.collect(WASAnnotationCollector.java:146)
        at 
com.ibm.ws.websvcs.desc.WSModuleDescriptorImpl.getClassDataObjects(WSModuleDescriptorImpl.java:1458)
        at 
com.ibm.ws.websvcs.desc.WSModuleDescriptorImpl.initDBCMap(WSModuleDescriptorImpl.java:2153)
        at 
com.ibm.ws.websvcs.desc.WSModuleDescriptorImpl.buildJAXWSServiceRefs(WSModuleDescriptorImpl.java:1137)
        at 
com.ibm.ws.websvcs.desc.WSModuleDescriptorImpl._containsWebServiceClients(WSModuleDescriptorImpl.java:639)
        at 
com.ibm.ws.websvcs.desc.WSModuleDescriptorImpl.containsWebServiceClients(WSModuleDescriptorImpl.java:611)
        at 
com.ibm.ws.websvcs.deploy.WSCacheWriter.writeModuleCache(WSCacheWriter.java:583)
        at 
com.ibm.ws.websvcs.deploy.WSCacheWriter.writeApplicationCache(WSCacheWriter.java:242)
        at 
com.ibm.ws.websvcs.deploy.WSCacheWriter.writeApplicationCache(WSCacheWriter.java:167)
        at 
com.ibm.ws.websvcs.deploy.PersistentStorageInstallSaveTask.performTask(PersistentStorageInstallSaveTask.java:196)
        at 
com.ibm.ws.management.application.sync.AppBinaryProcessor$ExpandApp.expand(AppBinaryProcessor.java:1770)
        at 
com.ibm.ws.management.application.sync.AppBinaryProcessor$AppBinThread.run(AppBinaryProcessor.java:1276)
        at java.lang.Thread.run(Thread.java:811)
Caused by: java.lang.IllegalArgumentException
        at org.objectweb.asm.ClassReader.<init>(Unknown Source)
        at org.objectweb.asm.ClassReader.<init>(Unknown Source)
        at org.objectweb.asm.ClassReader.<init>(Unknown Source)
        at 
com.ibm.ws.metadata.annotations.AnnotationConfigReader.getAnnotationData(AnnotationConfigReader.java:836)
        ... 18 more
(...)

Switching back to the older 1.7.25 version lets this error message 
disappear.

The reason is that Websphere uses Java 8 which cannot parse / process the 
module-info.class that was compiled with Java 9.

Solution for these kinds of problems:
Move the class to META-INF/versions/9 and mark the resulting Jar as a 
multi-release. See [1] for how to do this.

What do you think?
I can create a pull request on Github if you like.

Regards

Thorsten

[1] 
https://github.com/apache/maven-compiler-plugin/blob/master/src/it/multirele...

[slf4j-dev] SLF4J 1.8 on JVMs < 9

Thorsten Heit