Sergei Kharkhardin created LOG4J2-1747:
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Summary: Improper class bundling for an OSGi container's
environment.
Key: LOG4J2-1747
URL: https://issues.apache.org/jira/browse/LOG4J2-1747
Project: Log4j 2
Issue Type: Bug
Components: API, Core
Affects Versions: 2.7
Environment: Eclipse Equinox OSGi container
Reporter: Sergei Kharkhardin
I use org.apache.logging.log4j:log4j-api:2.7 and
org.apache.logging.log4j:log4j-core:2.7 from Maven Central Repository.
During a OSGi container's startup I get the following exception:
org.osgi.framework.BundleException: Exception in
org.eclipse.gemini.web.tomcat.internal.Activator.start() of bundle
org.eclipse.gemini.web.tomcat.
at
org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:792)
at
org.eclipse.osgi.internal.framework.BundleContextImpl.start(BundleContextImpl.java:721)
at
org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(EquinoxBundle.java:941)
at
org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(EquinoxBundle.java:318)
at org.eclipse.osgi.container.Module.doStart(Module.java:571)
at org.eclipse.osgi.container.Module.start(Module.java:439)
at
org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1582)
at
org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1562)
at
org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.doContainerStartLevel(ModuleContainer.java:1533)
at
org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1476)
at
org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1)
at
org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at
org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)
Caused by: java.lang.NoClassDefFoundError:
org/apache/logging/log4j/ThreadContextAccess
at
org.apache.logging.log4j.core.impl.ContextDataInjectorFactory.createDefaultInjector(ContextDataInjectorFactory.java:83)
at
org.apache.logging.log4j.core.impl.ContextDataInjectorFactory.createInjector(ContextDataInjectorFactory.java:67)
at
org.apache.logging.log4j.core.lookup.ContextMapLookup.<init>(ContextMapLookup.java:34)
at
org.apache.logging.log4j.core.lookup.Interpolator.<init>(Interpolator.java:116)
at
org.apache.logging.log4j.core.config.AbstractConfiguration.<init>(AbstractConfiguration.java:120)
at
org.apache.logging.log4j.core.config.NullConfiguration.<init>(NullConfiguration.java:32)
at
org.apache.logging.log4j.core.LoggerContext.<clinit>(LoggerContext.java:72)
at
org.apache.logging.log4j.core.osgi.BundleContextSelector.locateContext(BundleContextSelector.java:67)
at
org.apache.logging.log4j.core.osgi.BundleContextSelector.getContext(BundleContextSelector.java:53)
at
org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:57)
at
org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:147)
at
org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
at org.apache.logging.log4j.LogManager.getContext(LogManager.java:194)
at
org.apache.logging.log4j.spi.AbstractLoggerAdapter.getContext(AbstractLoggerAdapter.java:103)
at
org.apache.logging.slf4j.Log4jLoggerFactory.getContext(Log4jLoggerFactory.java:43)
at
org.apache.logging.log4j.spi.AbstractLoggerAdapter.getLogger(AbstractLoggerAdapter.java:42)
at
org.apache.logging.slf4j.Log4jLoggerFactory.getLogger(Log4jLoggerFactory.java:29)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:358)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:383)
at
org.eclipse.gemini.web.tomcat.internal.TomcatWebContainerProperties.<clinit>(TomcatWebContainerProperties.java:45)
at
org.eclipse.gemini.web.tomcat.internal.Activator.registerConnectorDescriptors(Activator.java:74)
at
org.eclipse.gemini.web.tomcat.internal.Activator.start(Activator.java:57)
at
org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:771)
at
org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:1)
at java.security.AccessController.doPrivileged(Native Method)
at
org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:764)
... 12 more
Caused by: java.lang.ClassNotFoundException:
org.apache.logging.log4j.ThreadContextAccess cannot be found by
org.apache.logging.log4j.core_2.7.0
at
org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:389)
at
org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:352)
at
org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:344)
at
org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 38 more
I would like to share the result of my investigation:
Analysis:
The reason of this exception is quite clear -
org.apache.logging.log4j.ThreadContextAccess cannot be found by
org.apache.logging.log4j.core_2.7.0
But, if you check the contents of log4j-core-2.7.jar you will see that class is
present there. It seems strange for regular Java class-loading based on
classpath. In an OSGi environment the class-loading rules a bit different, and
further analysis showed the following:
1. log4j-core bundle does not export org.apache.log4j package
2. log4j-api bundle do export org.apache.log4j package
3. log4j-api bundle is responsible for loading classes related to the
org.apache.log4j package but it does not contain ThreadContextAccess class.
Conclusion & Resolution:
This issue does not affect regular Java environment. It is actual only for OSGi
environments.
I see several possible solutions:
1. Move ThreadContextAccess class from log4j-core bundle into log4j-api bundle.
2. Move into different package inside log4j-core in order to prevent package'
name collisions with log4j-api.
I have tested #1 solution and it fixes the problem.
Hope you will fix this problem, as it actually a blocker issue for OSGi
applications.
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