- SE -- Affects the Java SE API or platform specification. For Java APIs, this is approximately the exported and public portions of java.* and javax.*. Other portions of the platform specification include the JNI specification, serialization specification, and so on.
- JDK -- Affects the JDK-specific API or platform, including public and exported jdk.* APIs
- Implementation -- An implementation-only change that does not affect any specification. (Such a change will most likely have behavioral compatibility impact.)