On Mon, 22 Sep 2025 17:08:20 GMT, Chen Liang <[email protected]> wrote:
>> Implementation changes for [JEP 500: Prepare to Make Final Mean >> Final](https://openjdk.org/jeps/500). >> >> Field.set (and Lookup.unreflectSetter) are changed to allow/warn/debug/deny >> when mutating a final instance field. JFR event recorded if final field >> mutated. Spec updates to Field.set, Field.setAccessible and Module.addOpens >> to align with the proposal in the JEP. >> >> HotSpot is updated to add support for the new command line options. To aid >> diagnosability, -Xcheck:jni reports a fatal error when a mutating a final >> field with JNI, and -Xlog:jni=debug can help identity when JNI code mutates >> finals. For now, JNI code is allowed to set the "write-protected" fields >> System.in/out/err, we can re-visit once we change the >> System.setIn/setOut/setErr methods to not use JNI (I prefer to keep this >> separate to this PR because there is a small startup regression to address >> when changing System.setXXX). >> >> There are many new tests. A small number of existing tests are changed to >> run /othervm as reflectively opening a package isn't sufficient. Changing >> the tests to /othervm means that jtreg will launch the agent with the >> command line options to open the package. >> >> Testing: tier1-6 > > src/java.base/share/classes/java/lang/reflect/Field.java line 1461: > >> 1459: return Modifier.isFinal(modifiers) >> 1460: && !Modifier.isStatic(modifiers) >> 1461: && !clazz.isRecord() > > This check cannot constant fold in the edge case where the declaring class > extends `java.lang.Record` but does not have a `Record` attribute. I have > seen such classes in proguard-stripped code. If this were to become an issue then we could separate the isFinal check. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/25115#discussion_r2369589705
