title: ElasticSearch java API to get multiple documents across indexes (using alias) using item id
body: <p>ElasticSearch has GET API using which we can query on a single index for a particular document using the document Id.
  From Elasticsearch 5.1, GET API supports querying on documents on an alias too that can point to multiple indexes like this:</p>
  
  <pre><code>GET /my_alias_name/_search/
  {
          "query": { 
          "bool": {
           "filter": {
                  "term": {
                     "_id": "AUwNrOZsm6BwwrmnodbW"
                  }
              }
          }
      }
  }
  </code></pre>
  
  <p>What is the corresponding JAVA API to achieve this (using JestClient...)?</p>