Java Puzzlers spring to mind. There's a book [0], and some fun talks available on youtube [1][2][3]. [0]: http://www.javapuzzlers.com/ http://www.javapuzzlers.

Java Puzzlers spring to mind. There's a book [0], and some fun talks available on youtube [1][2][3]. [0]: http://www.javapuzzlers.com/ http://www.javapuzzlers.com/ [1]: https://www.youtube.com/watch?v=wbp-3BJWsU8 https://www.youtube.com/watch?v=wbp-3BJWsU8 [2]: https://www.youtube.com/watch?v=yGFok5AJAyc https://www.youtube.com/watch?v=yGFok5AJAyc [3]: https://www.youtube.com/watch?v=Wnzyp1aitb8 https://www.youtube.com/watch?v=Wnzyp1aitb8