ConnectException using REST client in Java

Elastic Stack Elasticsearch
,
1

RestClient is initialised well, but while trying to use the high level client , getting the following error

java.net.ConnectException: null
        at org.apache.http.nio.pool.RouteSpecificPool.timeout(RouteSpecificPool.java:168)
        at org.apache.http.nio.pool.AbstractNIOConnPool.requestTimeout(AbstractNIOConnPool.java:561)
        at org.apache.http.nio.pool.AbstractNIOConnPool$InternalSessionRequestCallback.timeout(AbstractNIOConnPool.java:822)
        at org.apache.http.impl.nio.reactor.SessionRequestImpl.timeout(SessionRequestImpl.java:183)
        at 
org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor.processTimeouts(DefaultConnectingIOReactor.java:210)
        at org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor.processEvents(DefaultConnectingIOReactor.java:155)
        at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.execute(AbstractMultiworkerIOReactor.java:348)
        at org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager.execute(PoolingNHttpClientConnectionManager.java:189)
        at org.apache.http.impl.nio.client.CloseableHttpAsyncClientBase.doExecute(CloseableHttpAsyncClientBase.java:67)
        at org.apache.http.impl.nio.client.CloseableHttpAsyncClientBase.access$000(CloseableHttpAsyncClientBase.java:38)
        at org.apache.http.impl.nio.client.CloseableHttpAsyncClientBase$1.run(CloseableHttpAsyncClientBase.java:57)
        at java.lang.Thread.run(Thread.java:748)

Elasticsearch cluster version: 5.6.16
Client version: 5.6.16

      for (String host : hosts) {
        httpHosts[i++] = new HttpHost(host,  9200, HttpHost.DEFAULT_SCHEME_NAME);
      }
      RestClient lowlevelClient = RestClient.builder(httpHosts).build();
      RestHighLevelClient restClient =  new RestHighLevelClient(lowlevelClient);

I could able to hit and get value with this in cluster using 9200 port

curl -XGET http://ES_IP_ADDERESS:9200/*/_search
2

Will add if any extra details if needed

3

Welcome.

We don't support anymore 5.x and 6.x.
Go to at least 7.17 or better 8.1.