# Elasticsearch 2.0 java client **URL:** \ **Category:** Elasticsearch\ **Created:** [November 23, 2015, 12:58pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301 "2015-11-23T12:58:53Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![George](https://avatars.discourse-cdn.com/v4/letter/g/71e660/32.png) [@George](https://discuss.elastic.co/u/George)\ **Post date:** [November 23, 2015, 12:58pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301/1 "2015-11-23T12:58:53Z")
Hello, I'm trying to use the elasticsearch 2.0 java client and to create a transport node which connects to an elasticsearch 1.6.0 cluster. However, I'm getting this exception: 2015-11-23 13:32:02 WARN netty:723 - [Roma] exception caught on transport layer [[id: 0x26a9f009, /10.0.2.15:36369 =\> [example.com/153.65.234.45:9300](http://example.com/153.65.234.45:9300)]], closing connection java.lang.NullPointerException at org.elasticsearch.transport.netty.MessageChannelHandler.handleException(MessageChannelHandler.java:206) at org.elasticsearch.transport.netty.MessageChannelHandler.handlerResponseError(MessageChannelHandler.java:201) at org.elasticsearch.transport.netty.MessageChannelHandler.messageReceived(MessageChannelHandler.java:136) The question is, can we connect with a 2.0 java client to a 1.6.0 es cluster? Thanks! ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [November 23, 2015, 1:10pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301/2 "2015-11-23T13:10:43Z")
No. You can't. ---
**Author:** ![George](https://avatars.discourse-cdn.com/v4/letter/g/71e660/32.png) [@George](https://discuss.elastic.co/u/George)\ **Post date:** [November 23, 2015, 2:24pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301/3 "2015-11-23T14:24:46Z")
Ok thanks for the info. This does only apply for Transport nodes, right? Because when I tried to connect with a normal node, I didn't get any exception. ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [November 23, 2015, 2:47pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301/4 "2015-11-23T14:47:13Z")
Sorry. What is a "transport node"? ---
**Author:** ![George](https://avatars.discourse-cdn.com/v4/letter/g/71e660/32.png) [@George](https://discuss.elastic.co/u/George)\ **Post date:** [November 23, 2015, 2:48pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301/5 "2015-11-23T14:48:52Z")
Sorry, my Mistake, I meant TransportClient. [https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/transport-client.html](https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/transport-client.html) ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [November 23, 2015, 3:04pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301/6 "2015-11-23T15:04:27Z")
I think this should not work with: - Node Client - Transport Client Even if it works for some simple cases, don't mix 1.x versions with 2.x versions. Definitely not supported. ---
**Author:** ![George](https://avatars.discourse-cdn.com/v4/letter/g/71e660/32.png) [@George](https://discuss.elastic.co/u/George)\ **Post date:** [November 23, 2015, 3:04pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301/7 "2015-11-23T15:04:55Z")
Ok, thanks! ---
**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, 11:36pm UTC](https://discuss.elastic.co/t/elasticsearch-2-0-java-client/35301/8 "2017-07-05T23:36:34Z")