JEP 261 "The module system" states that the final format of JMOD files is an open issue. However it is not listed as an open issue here: http://openjdk.java.net/projects/jigsaw/spec/issues/ The format of JMOD files doesn't seem to be a part of the spec. Is this going to be resolved before launch? I understand that jimage files are HotSpot proprietary but my understanding was that JMODs were going to be a kind of upgrade to the JAR format and that'd be public.