JDK 9 was the impetus, but the real nail was, I think, 17 when a lot of the constraints imposed by the module system became required. Before that folks could p

JDK 9 was the impetus, but the real nail was, I think, 17 when a lot of the constraints imposed by the module system became required. Before that folks could pretty much continue as usual with little regard to the module system. After 17, legacy systems needed to start adding runtime options to work correctly. And, as I recall, this was mostly constrained to the dynamic, reflective, and introspective properties. Generic jars and code can still run without the module system. Unfortunately, a lot of the magic in modern Java is through those reflection aspects. So it made moving to 17+ an effort for many legacy code bases. And it should be clear, in general, all of the code was fine. It was all runtime options setting up package permissions that was the problem. Doesn’t make it less frustrating. (And I’m pretty sure 17 was the rubicon for this, but it may have been another version.)