What are some Java library for ReCaptcha that does not utilize Google ReCaptcha?

I am developing a ReCaptcha for a site. Because of client's requirement, I cannot use Google ReCaptcha and anything in the cloud. Basically, I need a library that can be installed on my local machine, does not make remote request when I use it. The library must be able to run in Java.

I have been trying to find such thing, but have had no luck. Does anyone know any?