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https://issues.apache.org/jira/browse/KAFKA-3218?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15137583#comment-15137583
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Rajini Sivaram commented on KAFKA-3218:
---------------------------------------
Not sure if a configuration option to choose between current classloader and
the context classloader is the right approach to support OSGi. While that may
work in this particular case where the class being loaded is the default
partitioner which is included in Kafka, in the general case, you might want to
load your own partitioner class contained in another bundle. Perhaps, it makes
sense to fix the default case in this JIRA without adding additional config and
raise a KIP to support OSGi properly?
> Kafka-0.9.0.0 does not work as OSGi module
> ------------------------------------------
>
> Key: KAFKA-3218
> URL: https://issues.apache.org/jira/browse/KAFKA-3218
> Project: Kafka
> Issue Type: Bug
> Components: clients
> Affects Versions: 0.9.0.0
> Environment: Apache Felix OSGi container
> jdk_1.8.0_60
> Reporter: Joe O'Connor
> Attachments: ContextClassLoaderBug.tar.gz
>
>
> 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:
> # install the kafka-clients servicemix OSGi module 0.9.0.0_1
> # attempt to initialize the Kafka producer client from Java code
> Expected results:
> - call to "new KafkaProducer()" succeeds
> Actual results:
> - "new KafkaProducer()" throws ConfigException:
> {quote} 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)
> {quote}
> 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
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