Gradle 6.9.2 is 5 years old (December 2021) and is preventing this project from using Java versions greater than 15, gradle java runtime compatibility matrix. The project is currently targeting java 8 as the source and target compatibility (source code), so how about updating to gradle 8.14.4 the latest version of gradle that supports Java 8.

Gave it a first go and found some issues below to discuss:

• overlapping jar and bootJar output addressed by spring boot 2.5.0+ (support ended for 2.5.0 2023-08) - logic exists to address this issue in jib-gradle-plugin and unit tests are failing. Should the logic be removed as well as the unit tests? The logic could be left in and the unit tests updated to keep support for legacy spring boot users.
• feature registration on main has been deprecated - Is zstd support still desired. A new source set can be created in jib-core, but it is unnecessary if the support is not still desired.

Welcome any thoughts.