# Concurrent Modification Exception being received **URL:** \ **Category:** Elasticsearch\ **Created:** [May 10, 2011, 10:53pm UTC](https://discuss.elastic.co/t/concurrent-modification-exception-being-received/4378 "2011-05-10T22:53:44Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Pat\_Christopher](https://avatars.discourse-cdn.com/v4/letter/p/f14d63/32.png) [@Pat\_Christopher](https://discuss.elastic.co/u/Pat_Christopher)\ **Post date:** [May 10, 2011, 10:53pm UTC](https://discuss.elastic.co/t/concurrent-modification-exception-being-received/4378/1 "2011-05-10T22:53:44Z")
Hi, I'm running ES 0.16.0 and I'm getting the following exception when creating a TransportClient: Exception in thread "main" java.util.ConcurrentModificationException at java.util.HashMap$HashIterator.nextEntry(Unknown Source) at java.util.HashMap$KeyIterator.next(Unknown Source) at org.elasticsearch.client.transport.TransportClientNodesService $ScheduledSniffNodesSampler.run(TransportClientNodesService.java:258) at org.elasticsearch.client.transport.TransportClientNodesService.addTransportAddress(TransportClientNodesService.java: 117) at org.elasticsearch.client.transport.TransportClient.addTransportAddress(TransportClient.java: 197) at com.mycom.pac.elasticsearch.example.ElasticSearchExample.main(ElasticSearchExample.java: 30) I'm creating a TransportClient node as follows: TransportClient client = new TransportClient(settingsBuilder().put("cluster.name","myCluster") .put("client.transport.sniff",true)) .addTransportAddress(new InetSocketTransportAddress("ec2-ip-address", 9300)); If I remove the client.transport.sniff settings put, the client connects correctly. Am I doing this wrong or is it a bug of some sort? Thanks, Pat ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [May 10, 2011, 11:01pm UTC](https://discuss.elastic.co/t/concurrent-modification-exception-being-received/4378/2 "2011-05-10T23:01:16Z")
Fixed: [Possible failure when using TransportClient (with sniffing) · Issue #923 · elastic/elasticsearch · GitHub](https://github.com/elasticsearch/elasticsearch/issues/923). Will be part of 0.16.1 which will be released in a couple of days. On Wednesday, May 11, 2011 at 1:53 AM, Pat Christopher wrote: > Hi, > I'm running ES 0.16.0 and I'm getting the following exception when > creating a TransportClient: > > Exception in thread "main" java.util.ConcurrentModificationException > at java.util.HashMap$HashIterator.nextEntry(Unknown Source) > at java.util.HashMap$KeyIterator.next(Unknown Source) > at org.elasticsearch.client.transport.TransportClientNodesService > $ScheduledSniffNodesSampler.run(TransportClientNodesService.java:258) > at > org.elasticsearch.client.transport.TransportClientNodesService.addTransportAddress(TransportClientNodesService.java: > 117) > at > org.elasticsearch.client.transport.TransportClient.addTransportAddress(TransportClient.java: > 197) > at > com.mycom.pac.elasticsearch.example.ElasticSearchExample.main(ElasticSearchExample.java: > 30) > > I'm creating a TransportClient node as follows: > > TransportClient client = new > TransportClient(settingsBuilder().put("cluster.name","myCluster") > .put("client.transport.sniff",true)) > .addTransportAddress(new > InetSocketTransportAddress("ec2-ip-address", 9300)); > > If I remove the client.transport.sniff settings put, the client > connects correctly. > > Am I doing this wrong or is it a bug of some sort? > > Thanks, > Pat ---
**Author:** ![Pat\_Christopher](https://avatars.discourse-cdn.com/v4/letter/p/f14d63/32.png) [@Pat\_Christopher](https://discuss.elastic.co/u/Pat_Christopher)\ **Post date:** [May 10, 2011, 11:09pm UTC](https://discuss.elastic.co/t/concurrent-modification-exception-being-received/4378/3 "2011-05-10T23:09:09Z")
yay! Thanks Shay. On May 10, 4:01 pm, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > Fixed:[Possible failure when using TransportClient (with sniffing) · Issue #923 · elastic/elasticsearch · GitHub](https://github.com/elasticsearch/elasticsearch/issues/923). Will be part of 0.16.1 which will be released in a couple of days. > > On Wednesday, May 11, 2011 at 1:53 AM, Pat Christopher wrote: > > > Hi, > > I'm running ES 0.16.0 and I'm getting the following exception when > > creating a TransportClient: > > > Exception in thread "main" java.util.ConcurrentModificationException > > at java.util.HashMap$HashIterator.nextEntry(Unknown Source) > > at java.util.HashMap$KeyIterator.next(Unknown Source) > > at org.elasticsearch.client.transport.TransportClientNodesService > > $ScheduledSniffNodesSampler.run(TransportClientNodesService.java:258) > > at > > org.elasticsearch.client.transport.TransportClientNodesService.addTransportAddress(TransportClientNodesService.java: > > 117) > > at > > org.elasticsearch.client.transport.TransportClient.addTransportAddress(TransportClient.java: > > 197) > > at > > com.mycom.pac.elasticsearch.example.ElasticSearchExample.main(ElasticSearchExample.java: > > 30) > > > I'm creating a TransportClient node as follows: > > > TransportClient client = new > > TransportClient(settingsBuilder().put("cluster.name","myCluster") > > .put("client.transport.sniff",true)) > > .addTransportAddress(new > > InetSocketTransportAddress("ec2-ip-address", 9300)); > > > If I remove the client.transport.sniff settings put, the client > > connects correctly. > > > Am I doing this wrong or is it a bug of some sort? > > > Thanks, > > Pat ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 4:06am UTC](https://discuss.elastic.co/t/concurrent-modification-exception-being-received/4378/4 "2017-07-06T04:06:31Z")