I "returned" to study artificial intelligence recently; my Computer Science degree thesis work was about Bayesian Networks and Genetic Algorithms. I used Weka library and an open source library developed at MIT (sorry, i don't remember its name).
But it was a life ago :-)
Now I'm refreshing my AI knowledge studying Deep Learning. Quite a buzzword I have to admit, but still really interesting. I think I'll try with numeral recognition.
I'd love to write my own simple framework to accomplish this, and honestly I don't know if I will use Java or not.