The get API allows to get a typed JSON document from the index based on its id. The following example gets a JSON document from an index called twitter, under a type called tweet, with id valued 1:
GetResponse response = client.prepareGet("twitter", "tweet", "1") .execute() .actionGet();
For more information on the index operation, check out the REST get docs.
The get API allows to set the threading model the operation will be performed when the actual execution of the API is performed on the same node (the API is executed on a shard that is allocated on the same server).
The options are to execute the operation on a different thread, or to execute it on the calling thread (note that the API is still async). By default, operationThreaded is set to true which means the operation is executed on a different thread. Here is an example that sets it to false:
GetResponse response = client.prepareGet("twitter", "tweet", "1") .setOperationThreaded(false) .execute() .actionGet();