This great primer for Contexts and Dependency Injection covers the need for it and a simple implementation in a Java EE environment that focuses on injecting properties.
Here's an introduction to logging with Log4j. If you aren't familiar with it already, take a look at what it offers and how to configure it for your Java projects.
Groovy now has extension methods and overloaded operators for the Java 8 Date/Time API types. Let's see them in action and how they can make coding easier.
Supplier is a versatile tool for development, so let's look at how you can use its offerings for lazy evaluation, and how to tell when that's the right choice.