It seems I need to write a CKAN search interface to integrate with a Java tool. I am wondering which api client library to use for it.
Two options right now are python library or a java library itself.
I have begin testing with Jackan (http://opendatatrentino.github.io/jackan/index.html) which is java ckan library. It seems to be easy to work with. Let me test it capabilities further. Jackan API docs http://opendatatrentino.github.io/jackan/0.4/javadoc/index.html.