# Unable to cast org.elasticsearch.client.RestClient to org.elasticsearch.client.Client
**URL:** https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488
**Category:** Elasticsearch
**Tags:** language-clients
**Created:** [August 11, 2020, 5:42am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488 "2020-08-11T05:42:19Z")
**Posts on this page:** 14
**Page:** 1
### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 11, 2020, 5:42am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/1 "2020-08-11T05:42:19Z")
Hi, In my code I am casting RestClient to Client. I don't see any runtime error but my application is not coming up due to the following error. Can someone help me
org.apache.catalina.core.StandardContext.listenerStart Exception sending context initialized event to listener instance of class [classname]
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'ESClient' defined in URL [\<\>]: Invocation of init method failed; nested exception is java.lang.ClassCastException: org.elasticsearch.client.RestClient cannot be cast to org.elasticsearch.client.Client
Also, I installed ES 7.8.1 version and I do not see org.elasticsearch.client.RestHighLevelClient in my package. Can you please help
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### Author:  [@TimV](https://discuss.elastic.co/u/TimV)
#### Post date: [August 11, 2020, 6:17am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/2 "2020-08-11T06:17:13Z")
Neither `RestClient` or `RestHighLevelClient` implement the `Client` interface. They are different clients with different methods.
You can't cast them like that.
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### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 11, 2020, 6:18am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/3 "2020-08-11T06:18:34Z")
Hmm basically I want to replace TransportClient which implements Client interface. How do I replace it so I can cast to Client.
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### Author:  [@TimV](https://discuss.elastic.co/u/TimV)
#### Post date: [August 11, 2020, 6:21am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/4 "2020-08-11T06:21:12Z")
You cannot do a drop in replacement for `TransportClient`. The `RestHighLevelClient` is the closest match, but it is not identical. You will need to make code changes to switch your application to use `RestHighLevelClient` instead.
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### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 11, 2020, 6:25am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/5 "2020-08-11T06:25:54Z")
Thank Tim. I am using ES 7.8.1 and in my package I do not find org.ealsticsearch.client.RestHighLevelClient. It is missing. I only see RestClient. Can you suggest what I am missing here.
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### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 11, 2020, 6:28am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/6 "2020-08-11T06:28:23Z")
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### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 11, 2020, 6:28am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/7 "2020-08-11T06:28:35Z")
I just see restclient
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### Author:  [@TimV](https://discuss.elastic.co/u/TimV)
#### Post date: [August 11, 2020, 6:35am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/8 "2020-08-11T06:35:48Z")
This might help: [https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.8/\_how\_to\_migrate.html](https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.8/_how_to_migrate.html)
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### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 11, 2020, 6:51am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/9 "2020-08-11T06:51:43Z")
Ok. Thanks Tim. Will try adding the dependency
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### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 11, 2020, 5:31pm UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/10 "2020-08-11T17:31:48Z")
Also how do I check if indicies and mapping exists in RestHighLevelClient. In transportclient which implements we do something like this client.admin().indices().prepareExists(index);
How can I do it using RestHighLevelClient. I don't see any such methods. Please suggest
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### Author:  [@TimV](https://discuss.elastic.co/u/TimV)
#### Post date: [August 12, 2020, 1:21am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/11 "2020-08-12T01:21:41Z")
It sounds like you want `client.indices().exists()`
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### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 12, 2020, 5:36am UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/12 "2020-08-12T05:36:14Z")
Thanks Tim. Yes, right now modifying the code.
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### Author:  [@elastic78](https://discuss.elastic.co/u/elastic78)
#### Post date: [August 13, 2020, 8:44pm UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/13 "2020-08-13T20:44:21Z")
Hi Tim, Currently we are using lucene version 6.6.0; do we need to even upgrade lucene to 8.5.1 if we want to upgrade ES to 7.8.1 or it is independent.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [September 10, 2020, 8:44pm UTC](https://discuss.elastic.co/t/unable-to-cast-org-elasticsearch-client-restclient-to-org-elasticsearch-client-client/244488/14 "2020-09-10T20:44:28Z")
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