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  1. Kafka
  2. KAFKA-3218

Kafka- does not work as OSGi module



    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s:
    • Fix Version/s:
    • Component/s: clients
    • Labels:
    • Environment:
      Apache Felix OSGi container


      KAFKA-2295 changed all Class.forName() calls to use currentThread().getContextClassLoader() instead of the default "classloader that loaded the current class".

      OSGi loads each module's classes using a separate classloader so this is now broken.

      Steps to reproduce:

      1. install the kafka-clients servicemix OSGi module
      2. attempt to initialize the Kafka producer client from Java code

      Expected results:

      • call to "new KafkaProducer()" succeeds

      Actual results:

      • "new KafkaProducer()" throws ConfigException:

        Suppressed: java.lang.Exception: Error starting bundle54: Activator start error in bundle com.openet.testcase.ContextClassLoaderBug [54].
        at org.apache.karaf.bundle.command.BundlesCommand.doExecute(BundlesCommand.java:66)
        ... 12 more
        Caused by: org.osgi.framework.BundleException: Activator start error in bundle com.openet.testcase.ContextClassLoaderBug [54].
        at org.apache.felix.framework.Felix.activateBundle(Felix.java:2276)
        at org.apache.felix.framework.Felix.startBundle(Felix.java:2144)
        at org.apache.felix.framework.BundleImpl.start(BundleImpl.java:998)
        at org.apache.karaf.bundle.command.Start.executeOnBundle(Start.java:38)
        at org.apache.karaf.bundle.command.BundlesCommand.doExecute(BundlesCommand.java:64)
        ... 12 more
        Caused by: java.lang.ExceptionInInitializerError
        at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:156)
        at com.openet.testcase.Activator.start(Activator.java:16)
        at org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:697)
        at org.apache.felix.framework.Felix.activateBundle(Felix.java:2226)
        ... 16 more
        Caused by: org.apache.kafka.common.config.ConfigException: Invalid value org.apache.kafka.clients.producer.internals.DefaultPartitioner for configuration partitioner.class: Class org.apache.kafka.clients.producer.internals.DefaultPartitioner could not be found.
        at org.apache.kafka.common.config.ConfigDef.parseType(ConfigDef.java:255)
        at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:78)
        at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:94)
        at org.apache.kafka.clients.producer.ProducerConfig.<clinit>(ProducerConfig.java:206)

      Workaround is to call "currentThread().setContextClassLoader(null)" before initializing the kafka producer.

      Possible fix is to catch ClassNotFoundException at ConfigDef.java:247 and retry the Class.forName() call with the default classloader. However with this fix there is still a problem at AbstractConfig.java:206, where the newInstance() call succeeds but "instanceof" is false because the classes were loaded by different classloaders.

      Testcase attached, see README.txt for instructions.

      See also SM-2743


        1. ContextClassLoaderBug.tar.gz
          4 kB
          Joe O'Connor

          Issue Links



              • Assignee:
                rsivaram Rajini Sivaram
                joconnor Joe O'Connor
              • Votes:
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                • Created: