elasticsearch/docs/java-rest/page_header.html

<p>
  <strong>WARNING</strong>: Deprecated in 7.15.0. 
</p>  
<p>
  The Java REST Client is deprecated in favor of the 
  <a href="https://www.elastic.co/guide/en/elasticsearch/client/java-api-client/current/index.html">Java API Client</a>.
</p>