[
https://issues.apache.org/jira/browse/KAFKA-3218?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Rajini Sivaram updated KAFKA-3218:
----------------------------------
Status: Patch Available (was: Open)
The PR addresses the loading of default classes for configuration properties by
switching to static classloading to enable Kafka classes to be loaded in
different environments like JEE, OSGi etc. which use different classloading
strategies. Most properties supplied by the application (eg. key.serializer)
can already be specified as classes to avoid relying on the current
classloading strategy in Kafka:
{quote}
properties.put("key.serializer",
org.apache.kafka.common.serialization.StringSerializer.class)
{quote}
Joe, can you check if this solution works for you?
To enable all features of Kafka to work well in OSGi, all uses of dynamic
classloading need to be fixed. This needs more work and it would be better to
do this with a KIP.
> 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
> Assignee: Rajini Sivaram
> 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
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
