# ElasticSeach java client ocasionally throws NoClassDefFoundError

**URL:** <https://discuss.elastic.co/t/elasticseach-java-client-ocasionally-throws-noclassdeffounderror/26148>\
**Category:** Elasticsearch\
**Created:** [July 23, 2015, 11:05am UTC](https://discuss.elastic.co/t/elasticseach-java-client-ocasionally-throws-noclassdeffounderror/26148 "2015-07-23T11:05:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Andreano24](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@Andreano24](https://discuss.elastic.co/u/Andreano24)\
**Post date:** [July 23, 2015, 11:05am UTC](https://discuss.elastic.co/t/elasticseach-java-client-ocasionally-throws-noclassdeffounderror/26148/1 "2015-07-23T11:05:55Z")

</div>

We're using ES java client 1.5.2 to communicate with our ES cluster(cluster obviously has the same version). Several times in week we observe following errors:

```
Exception in thread "elasticsearch[waElasticSearchNode][management][T#3]" Exception in thread "elasticsearch[waElasticSearchNode][management][T#4]" java.lang.NoClassDefFoundError: org/elasticsearch/common/netty/channel/Channels$7
    at org.elasticsearch.common.netty.channel.Channels.fireExceptionCaughtLater(Channels.java:496)
    at org.elasticsearch.common.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:46)
    at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.notifyHandlerException(DefaultChannelPipeline.java:658)
    at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.sendDownstream(DefaultChannelPipeline.java:577)
    at org.elasticsearch.common.netty.channel.Channels.close(Channels.java:812)
    at org.elasticsearch.common.netty.channel.AbstractChannel.close(AbstractChannel.java:206)
    at org.elasticsearch.transport.netty.NettyTransport$NodeChannels.caloseChannelsAndWait(NettyTransport.java:1098)
    at org.elasticsearch.transport.netty.NettyTransport$NodeChannels.close(NettyTransport.java:1084)
    at org.elasticsearch.transport.netty.NettyTransport.disconnectFromNode(NettyTransport.java:873)
    at org.elasticsearch.transport.TransportService.disconnectFromNode(TransportService.java:224)
    at org.elasticsearch.client.transport.TransportClientNodesService$SniffNodesSampler$1.run(TransportClientNodesService.java:477)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
java.lang.NoClassDefFoundError: org/elasticsearch/common/netty/channel/Channels$7
    at org.elasticsearch.common.netty.channel.Channels.fireExceptionCaughtLater(Channels.java:496)
    at org.elasticsearch.common.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:46)
    at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.notifyHandlerException(DefaultChannelPipeline.java:658)
    at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.sendDownstream(DefaultChannelPipeline.java:577)
    at org.elasticsearch.common.netty.channel.Channels.close(Channels.java:812)
    at org.elasticsearch.common.netty.channel.AbstractChannel.close(AbstractChannel.java:206)
    at org.elasticsearch.transport.netty.NettyTransport$NodeChannels.closeChannelsAndWait(NettyTransport.java:1098)
    at org.elasticsearch.transport.netty.NettyTransport$NodeChannels.close(NettyTransport.java:1084)
    at org.elasticsearch.transport.netty.NettyTransport.disconnectFromNode(NettyTransport.java:873)
    at org.elasticsearch.transport.TransportService.disconnectFromNode(TransportService.java:224)
    at org.elasticsearch.client.transport.TransportClientNodesService$SniffNodesSampler$1.run(TransportClientNodesService.java:477)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
Exception in thread "elasticsearch[waElasticSearchNode][management][T#1]" java.lang.NoClassDefFoundError: org/elasticsearch/common/netty/channel/Channels$7
    at org.elasticsearch.common.netty.channel.Channels.fireExceptionCaughtLater(Channels.java:496)
    at org.elasticsearch.common.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:46)
    at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.notifyHandlerException(DefaultChannelPipeline.java:658)
    at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.sendDownstream(DefaultChannelPipeline.java:577)
    at org.elasticsearch.common.netty.channel.Channels.close(Channels.java:812)
    at org.elasticsearch.common.netty.channel.AbstractChannel.close(AbstractChannel.java:206)
    at org.elasticsearch.transport.netty.NettyTransport$NodeChannels.closeChannelsAndWait(NettyTransport.java:1098)
    at org.elasticsearch.transport.netty.NettyTransport$NodeChannels.close(NettyTransport.java:1084)
    at org.elasticsearch.transport.netty.NettyTransport.disconnectFromNode(NettyTransport.java:873)
    at org.elasticsearch.transport.TransportService.disconnectFromNode(TransportService.java:224)
    at org.elasticsearch.client.transport.TransportClientNodesService$SniffNodesSampler$1.run(TransportClientNodesService.java:477)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
Exception in thread "elasticsearch[waElasticSearchNode][transport_client_worker][T#7]" at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
java.lang.NullPointerException
    at org.elasticsearch.transport.netty.NettyInternalESLogger.warn(NettyInternalESLogger.java:83)
    at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:340)
Exception in thread "elasticsearch[waElasticSearchNode][transport_client_worker][T#13]" at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89)
    at org.elasticsearch.common.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)
    at org.elasticsearch.common.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)
    at org.elasticsearch.common.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
java.lang.NullPointerException
    at org.elasticsearch.transport.netty.NettyInternalESLogger.warn(NettyInternalESLogger.java:83)
    at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:340)
    at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89)
    at org.elasticsearch.common.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)
Exception in thread "elasticsearch[waElasticSearchNode][transport_client_worker][T#26]" at org.elasticsearch.common.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)
    at org.elasticsearch.common.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
java.lang.NullPointerException
    at org.elasticsearch.transport.netty.NettyInternalESLogger.warn(NettyInternalESLogger.java:83)
    at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:340)
    at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89)
    at org.elasticsearch.common.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)
    at org.elasticsearch.common.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)
    at org.elasticsearch.common.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

```

We have no solid idea why it happens, any suggestions would be appreciated

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 5, 2017, 11:59pm UTC](https://discuss.elastic.co/t/elasticseach-java-client-ocasionally-throws-noclassdeffounderror/26148/2 "2017-07-05T23:59:32Z")

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