It's been more than a couple of years or so since JDK 9 was launched, and the new year is probably the best time to learn Java 9 and get yourself familiar with new features and enhancements on existing APIs. The highlight of the JDK 9 release was Project Jigsaw or Module system. The Java 9 Platform Module System allows Java to move forward by modularizing the JDK as well as adding modules as first-class citizens to Java, but that's not the only thing to look forward to, there are many small changes that are very useful in day-to-day coding.
