From case 02054234. Up through and including Jasper 7.9.0, customization classes must be built with Java 8 byte code or earlier. Setting the byte code to Java 11 is not supported by the version of Jersey that is bundled ( 2.25.1).
We cannot upgrade the Jersey version without changing the Jasper source code, because there are dependencies on internal Jersey classes for Spring dependency injection to work, and these internal classes have changed in 2.26.
Considering that Java 8 stopped getting public updates in January 2019, and will stop all non-security updates in March of next year, it's time for Jasper to move to Java 11. Plus the version of Jersey being used is quite old (Jan 2017), there have been numerous updates since then.
The work should be minor. Just move to a new version of Jersey and update the references to the internal Jersey classes so that dependency injection continues to function.