While it's easy to write a JSON query and directly use it with the Python client, using Java client requires a bit of expertise to create queries using Elasticsearch Java APIs.

In Java, there is the QueryBuilder class that helps you in constructing queries. Once the queries are created, you can execute that query with the client's prepareSearch method.

First of all, you need the following imports in your code:

import org.elasticsearch.index.query.QueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;

Then you can start building queries and executing them:

QueryBuilder query = QueryBuilders.termQuery("screen_name", "d_bharvi");
SearchResponse response = client.prepareSearch()
    .setIndices(indexName).setTypes(docType)
    .setQuery(query).setFrom(0).setSize(10)
    .execute().actionGet();

The preceding code shows an example of creating term queries where we search for a term, d_bharvi, inside the screen_name field.

Similarly, you can create all types of query against the QueryBuilders class. To take another example, a match_all query can be created by this:

QueryBuilders.matchAllQuery();

The other parameters are as follows:

SearchHit[] results = response.getHits().getHits();
        for (SearchHit hit : results) {
            System.out.println(hit.getSource());
            //process documents
        }