Delete multiple documents from an index in ElasticSearch with value of one of items - 7.8 version

my doc in elsticsearch is like below

    "hits" : [
      {
        "_index" : "MyIndex",
        "_type" : "_doc",
        "_id" : "Lxh7THMBycWRIeJFdwbZ",
        "_score" : 1.0,
        "_source" : {
          "@timestamp" : "2020-07-14T13:10:26.087+0430",
          "message" : "elk: customer inserted: id=5",
          "traceId" : "ABC",
          "severity" : "INFO",
          "thread" : "http-nio-8095-exec-2"
        }
      }
]

I want to delete All docs in one index that "traceId" : "ABC" with java code. I use Elasticsearch 7.8 and my client is RestHighLevelClient. please guide me.

The below sample code should help. You can refer to the links below to go through the API and understand what needs to be done in steps.

Basically every request sent via Java would have below two parts.

• Something similar to HttpClient for every request sent to elasticsearch i.e. High Level Rest Client.
• API Specific Query which in our case is Delete by Query

As for your example, note that I'm assuming that traceId.keyword is the field of type keyword and hence I'm using TermBuilder i.e. Term Query. If it is of type text I've mentioned Match Query in the comment, you would have to use that.

Sample Code

import java.io.IOException;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.TermQueryBuilder;
import org.elasticsearch.index.reindex.BulkByScrollResponse;
import org.elasticsearch.index.reindex.DeleteByQueryRequest;

public class DeleteBasedOnQuery {

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

        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));

        deleteQueryUsingMatch(client);

        client.close();

    }
    
    private static void deleteQueryUsingMatch(RestHighLevelClient client) throws IOException {
        
        //Mention index name
        DeleteByQueryRequest request = new DeleteByQueryRequest("my_delete_index");
        request.setConflicts("proceed"); 
        request.setBatchSize(100);
        request.setRefresh(true); 
        
        //Term Query to Delete the document. Note the field name and value in below code
        request.setQuery(new TermQueryBuilder("traceId.keyword", "ABC"));
        
        //Match Query to Delete the Document
        //request.setQuery(QueryBuilders.matchQuery("traceID", "abc"));
        
        //Execute the request to delete based on above details
        BulkByScrollResponse bulkResponse = client.deleteByQuery(request, RequestOptions.DEFAULT);
        
        //By this time your delete query got executed and you have the response with you. 
        long totalDocs = bulkResponse.getTotal(); 
        long deletedDocs = bulkResponse.getDeleted(); 
        
        //Print the response details
        System.out.println("Total Docs Processed :: " +  totalDocs);
        System.out.println("Total Docs Deleted :: " +  deletedDocs);        
        
    }

}