Although Multi-Release JAR files were introduced with Java 9 at the same time as Jigsaw (JPMS), this feature has been overshadowed by others, especially Jigsaw, JShell or even the Platform Logging API. This could be part of the reason why most of the popular build tools and also major IDEs don't really support it out of the box even more than 3 years after it was introduced. A lack that affects both the creation of a multi-release JAR file and using it in your application. Combining it with the JPMS or a true multi-release (not just a double-release) JAR add further challenges and complexity.
This session briefly explains why multi-release JARs exist and how they work. Followed by a hands-on journey from creating a multi-release JAR file for two or more Java versions including JPMS modularity to using such a multi-release JAR in your own application. It highlights common patterns for the creation of multi-release JAR files with build tools like Maven or Gradle. Including best practices for continuous build and deployment. And what to watch out for when using them in your own application.
Knowing a bit of Java can't hurt, but you don't have to be Hercules to be fit for the task.