JDK 8 introduced @jdk.Exported to help document the supported-ness of JDK-specific APIs.
Modules makes this annotation redundant and we should consider whether to deprecate or remove it in JDK 9.
It may be simplest to just remove it. The compatibility impact is likely to be low as it's not obvious that anything outside of the JDK is using it. Another point is that Java SE modules will only export Java SE APIs and therefore the jdk package would need to be exported by a JDK-specific - there are no obvious candidates at the moment as we have yet to introduce a jdk.base module.