This deep dive into Java 9 module services tackles how the ServiceLoader class has changed, how to browse the classpath, and how it all ties together in Jigsaw.
Get your feet wet with Java 9's modularity by learning how to create, compile, and execute single- and multi-module projects all from the command line.
Walk through my experience with querying an RDS MySQL database with AWS lambda for the first time, and the issues that I came across that you can avoid.
Take a look at how a Jackson mix-in class or interface, as well as some annotations, can help you with (de)serialization when you don't have source code access to POJOs.
JIRA's querying language, JQL, can be extremely useful. Look at some secrets when it comes to JQL that can help you make more effective use of your own JIRA instance.