Details
Description
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:
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
Attachments
Attachments
Issue Links
- relates to
-
KAFKA-2295 Dynamically loaded classes (encoders, etc.) may not be found by Kafka Producer
- Resolved
-
SM-2743 Create OSGi bundles for Kafka 0.9.0.0
- Resolved
- links to