> The class code org.basex.server.ClientSession coincides roughly with the class code BaseXClient.java provided as an example of Java client in https://github.com/BaseXdb/basex-api/tree/master/src/main/java?

The code is basically equivalent, but the files in the API package don't have any BaseX class dependencies. The performance should be pretty much the same, too.

Hope this helps,
Christian