On Sun, 30 May 2021 20:06:49 GMT, Jaroslav Tulach <github.com+26887752+jaroslavtul...@openjdk.org> wrote:
> My use-case relates to > [@JavaScriptBody](https://bits.netbeans.org/html+java/1.7.1/net/java/html/js/package-summary.html) > annotation used for Java/JavaScript interop. Originally all existing usages > (Post Processing Classes, Instrumentation Agent, Special classloading, etc.) > of the annotation performed the manipulation on `.class` files. However > recently a new use-case relying on JVMCI appeared. JVMCI is working on "live" > classes and doesn't provide access to the `.class` files (as far as I know, > CCing @dougxc). Using `-XX:+PreserveAllAnnotation` solved the first part of > problem - the HotSpot code loaded the `RuntimeInvisibleAnnotations`"in". The > second part was solved by on the fly patching of `@JavaScriptBody` class to > claim to have`RetentionPolicy.RUNTIME`. That part is a bit tricky, so I > created this pull request for your consideration. > > Obvious suggestion is to change the `@JavaScriptBody` retention to `RUNTIME` > - however there are plenty of libraries already compiled with the existing > annotation and they would have to be all recompiled to new version. I'd > rather avoid that and that's another reason why I decided to bring the > `-XX:+PreserveAllAnnotation` to your attention and propose to improve it. Hi Jaroslav, If you change `@JavaScriptBody` retention to `RUNTIME`, you don't need to re-compile any code that uses this annotation. You just have to use `-XX:+PreserveAllAnnotations` to expose all anotations to JVM and consequently to AnnotationParser. The parser will then return just the `RUNTIME` retention-marked annotations. This means you just have to run the app with the version of the JavaScriptBody.class that is retention-marked as `RUNTIME`... I think that `-XX:+PreserveAllAnnotations` was meant as a migration aid for exactly the case when some annotations migrate from `CLASS` to `RUNTIME` retention and libraries using such annotations are not re-compiled yet. ------------- PR: https://git.openjdk.java.net/jdk/pull/4245
