Cheaper resources have lead people away from app servers and WAR archives towards the easier Fat JAR approach. There is a chance that Docker will bring the WAR back.
Learn how the Groovy component is used in Mule flows to integrate custom scripts. This tutorial shows you how to configure and utilize the Groovy component.
You might see Spring's DelegatingFilterProxy crop up sometimes. It's actually a proxy for a standard Servlet Filter. Let's see an example in action with Spring Security.
VisualVM is one of those indispensable tools for Java (and JVM-based) developers. An oft-unsung hero, this post tells you what it is, how to set it up, and its benefits.