We plan on deprecating the TransportClient in Elasticsearch 7.0 and removing it completely in 8.0. Instead, you should be using the Java High Level REST Client, which executes HTTP requests rather than serialized Java requests.

MultiSearchRequest request = new MultiSearchRequest();

SearchRequest firstSearchRequest = new SearchRequest();

SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

searchSourceBuilder.query(QueryBuilders.matchQuery("user", "kimchy"));

firstSearchRequest.source(searchSourceBuilder);

request.add(firstSearchRequest);

SearchRequest secondSearchRequest = new SearchRequest();

searchSourceBuilder = new SearchSourceBuilder();

searchSourceBuilder.query(QueryBuilders.matchQuery("user", "luca"));

secondSearchRequest.source(searchSourceBuilder);

request.add(secondSearchRequest);

MultiSearchResponse response = client.msearch(request, RequestOptions.DEFAULT);

SearchRequestBuilder srb1 = client

    .prepareSearch().setQuery(QueryBuilders.queryStringQuery("elasticsearch")).setSize(1);

SearchRequestBuilder srb2 = client

    .prepareSearch().setQuery(QueryBuilders.matchQuery("name", "kimchy")).setSize(1);

MultiSearchResponse sr = client.prepareMultiSearch()

        .add(srb1)

        .add(srb2)

        .get();

// You will get all individual responses from MultiSearchResponse#getResponses()

long nbHits = 0;

for (MultiSearchResponse.Item item : sr.getResponses()) {

    SearchResponse response = item.getResponse();

    nbHits += response.getHits().getTotalHits();

}

import java.io.IOException;

import java.net.InetAddress;

import org.elasticsearch.action.search.MultiSearchResponse;

import org.elasticsearch.action.search.MultiSearchResponse.Item;

import org.elasticsearch.action.search.SearchRequest;

import org.elasticsearch.client.transport.TransportClient;

import org.elasticsearch.common.settings.Settings;

import org.elasticsearch.common.transport.TransportAddress;

import org.elasticsearch.search.builder.SearchSourceBuilder;

import org.elasticsearch.transport.client.PreBuiltTransportClient;

public class App4 {

    @SuppressWarnings("resource")

    public static void main(String[] args) throws IOException {

            TransportClient client=new PreBuiltTransportClient(Settings.EMPTY)

                    .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300)); //1st ES Node host and port

            SearchRequest req=new SearchRequest("person");

             SearchSourceBuilder builder=new SearchSourceBuilder();

             builder.size(10);

             req.source(builder);

             SearchRequest req1=new SearchRequest("posts");

             SearchSourceBuilder builder1=new SearchSourceBuilder();

             builder.size(10);

             req.source(builder1);

            MultiSearchResponse bulkResponse=client.prepareMultiSearch()

                    .add(req)

                    .add(req1)

                    .get();

            for (Item item : bulkResponse.getResponses()) {

                if (item.isFailure()) {

                    System.out.println(item.getFailureMessage());

                }else {

                    System.out.println("-----------------------------------------------------------------------");

                    System.out.println(item.getResponse().toString());

                }

            }

        /**** Done ****/

        System.out.println("Done");

    }

}