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Posted to dev@kafka.apache.org by "Bharat Viswanadham (JIRA)" <ji...@apache.org> on 2017/06/01 18:30:04 UTC

[jira] [Commented] (KAFKA-5229) Reflections logs excessive warnings when scanning classpaths

    [ https://issues.apache.org/jira/browse/KAFKA-5229?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16033453#comment-16033453 ] 

Bharat Viswanadham commented on KAFKA-5229:
-------------------------------------------

Moved to major, as first time users might feel this is a issue.
And also the stack trace is shown on the user screen, which will not be good.

> Reflections logs excessive warnings when scanning classpaths
> ------------------------------------------------------------
>
>                 Key: KAFKA-5229
>                 URL: https://issues.apache.org/jira/browse/KAFKA-5229
>             Project: Kafka
>          Issue Type: Bug
>          Components: KafkaConnect
>    Affects Versions: 0.10.0.0, 0.10.0.1, 0.10.1.0, 0.10.1.1, 0.10.2.0, 0.10.2.1
>            Reporter: Ewen Cheslack-Postava
>            Assignee: Bharat Viswanadham
>              Labels: newbie
>
> We use Reflections to scan the classpath for available plugins (connectors, converters, transformations), but when doing so Reflections tends to generate a lot of log noise like this:
> {code}
> [2017-05-12 14:59:48,224] WARN could not get type for name org.jboss.netty.channel.SimpleChannelHandler from any class loader (org.reflections.Reflections:396)
> org.reflections.ReflectionsException: could not get type for name org.jboss.netty.channel.SimpleChannelHandler
> 	at org.reflections.ReflectionUtils.forName(ReflectionUtils.java:390)
> 	at org.reflections.Reflections.expandSuperTypes(Reflections.java:381)
> 	at org.reflections.Reflections.<init>(Reflections.java:126)
> 	at org.apache.kafka.connect.runtime.PluginDiscovery.scanClasspathForPlugins(PluginDiscovery.java:68)
> 	at org.apache.kafka.connect.runtime.AbstractHerder$1.run(AbstractHerder.java:391)
> 	at java.lang.Thread.run(Thread.java:745)
> Caused by: java.lang.ClassNotFoundException: org.jboss.netty.channel.SimpleChannelHandler
> 	at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
> 	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
> 	at java.security.AccessController.doPrivileged(Native Method)
> 	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
> 	at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
> 	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
> 	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
> 	at org.reflections.ReflectionUtils.forName(ReflectionUtils.java:388)
> 	... 5 more
> {code}
> Despite being benign, these warnings worry users, especially first time users.
> We should either a) see if we can get Reflections to turn off these specific warnings via some config or b) make Reflections only log at > WARN by default in our log4j config. (b) is probably safe since we should only be seeing these at startup and I don't think I've seen any actual issue logged at WARN.



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