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  1. Log4j 2
  2. LOG4J2-373

Classloader issue in OSGi-environment

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Details

    • Bug
    • Status: Resolved
    • Critical
    • Resolution: Fixed
    • 2.0-beta9
    • 2.0.1
    • API, Core
    • OSGi R5 / R4 (Apache Felix 4.x)

    Description

      Using Log4j2 in a bundle causes following error:
      ERROR StatusLogger org.apache.logging.log4j.core.impl.Log4jContextFactory does not implement org.apache.logging.log4j.spi.LoggerContextFactory
      ERROR StatusLogger Unable to locate a logging implementation, using SimpleLogger

      printing the ClassLoaders in LogManager gives me following output:

      org.apache.logging.log4j.spi.LoggerContextFactory loaded by org.apache.logging.log4j-api [13]
      org.apache.logging.log4j.core.impl.Log4jContextFactory loaded by sun.misc.Launcher$AppClassLoader@35a16869

      We have two different ClassLoaders. That's why the implementation is not assignable. The core uses the bootstrap-classloader and the api uses the bundle-classloader.

      Workaround needed. Thx

      addendum:
      ProviderUtil.findClassLoader() returns the bootstrap-classloader but not the bundle-classloader of the log4j2-core. The log4j2-core is a fragment of the log4j2-api bundle. Thus, ProviderUtil.findClassLoader() must return the bundle-classloader of log4j2-api. This a bug for the case that log4j2-core is used as the implementation. There are other cases that will also cause problems. Further investigations are necessary.

      Workaround:
      1. check if log4j2 runs in an OSGI container.
      Bundle mybundle = org.osgi.framework.FrameworkUtil.getBundle(MyClass.this);
      2. if(mybundle != null), than get bundle-classloader of log4j2-impl.
      mybundle.adapt(BundleWiring.class).getClassLoader();

      Attachments

        1. log4j-api.patch
          2 kB
          Roland Weiglhofer

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              mattsicker Matt Sicker
              rol Roland Weiglhofer
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                Updated:
                Resolved: