Java One 2015 happened this week. There were so many interesting sessions you could nearly throw a dart at a dartboard with topics and go to the one you selected at random. For starters, here's a link to descriptions of the keynotes. And, you can check out the session descriptions here. 

The Java language celebrates it's 20th year this year.Here's a free book you can download: Introducing Java 8: A Quick-Start Guide to Lambdas and Streams. Java SE 8 is perhaps the largest change to Java in its history, led by its flagship feature—lambda expressions. If you’re an experienced developer looking to adopt Java 8 at work, this short guide will walk you through all of the major changes before taking a deep dive into lambda expressions and Java 8’s other big feature: the Streams API.