Ask HN: Good tech conferences in Europe for 2014

We are doing budget planning for 2014 to attend a tech conference. We are in new england, but I would like to find something in Europe to get the feeling on how is the dev env over there. We use spring, java on a daily basis. I am also interested on machine learning may be something to apply ML in business.

This is the best I have found so far in the US.(2013) https://springone2gx.com/conference/santa_clara/2013/09/springone/event_schedule