IntelliJ IDEA Community Edition 14.1.3

The installer takes up about 195MB of disk space and then expands into around 550 MB. The UI theme can be set to IntelliJ (default) or Darcula (black background, with orange keywords e.g. import, new etc,). The next phase of the installer is Default Plugins (Java Frameworks such as JBoss Seam, Struts, Spring, J2EE), and Build Tools (ant, maven, gradle) and Web Development (HTML, JavaScript). There is also IdeaVIM, a VIM plugin which is not recommended - even if you are familiar with VIM. A Scala plugin is also an optional extra.

More Respect for Object-Relational Mapping in Java through JPA

As mentioned before, JPA is important. What JPA is can be understood here.

Groovy in Action

Learning how to script in Groovy can be daunting without some extra help.

Here are some learning tips and resources.

BOOKS

"Groovy in Action" by technology publishers Manning Publications (2007) is a great introduction which doubles up as a helpful code mentor which will get you Groovy-ing in no time - without having to traipse the Interweb for code samples!

TOOLS

groovysh - is the groovy shell..  When you are done, type :x to exit the shell
groovyConsole - loads and runs groovy files

RxJava - Reactive Extensions for Java

The library for asynchronous, stream-based programming has come to Java. Sample it on GitHub. Here's the same project for Scala.

JavaOne 2014 in September 2014 in San Francisco

Neo4j will be presenting on its graph query engine for graph databases. Gradle build automation will also be discussed.

Project Valhalla as the Proving Ground for Prototyping Java 9 Features

JDK 9 is scheduled for 2016. Valhalla provides a testbed to trial new features as part of Open JDK. One of these is generics (removing type erasure). Brian Goetz's thoughts on these are here.

Road to Clojure (PC and JC)

Clojure is a LISP dialect for the JVM. It also allows you to call Java code from LISP. Books on Clojure include:

Programming Clojure, by Stuart Halloway and Aaron Bedra, available from the Pragmatic Bookshelf
The Joy of Clojure, by Michael Fogus and Chris Houser (May 2014)

Knowing the standard Java APIs is useful when learning Clojure.

LISP stands for List Processing and was a favourite with AI researchers back in the day, having been invented by John McCarthy in 1958. He published his design in CACM in 1960.