Fedora Project has a dedicated Java developer page:
There are tons of resources for Java development, like: https://developers.redhat.com/blog/category/java/
For debugging or development, there are
- openjfx (JavaFX)
- JavaFX (?) JavaFX is supposed to be merged in Java 8. Why is there a specific package??
Teaching and Learning Java
As part of planning and implementing new 100% FLOSS Java components into Fedora, this draft document has been opened to give developers a place to teach each other about best practices, patterns, etc.