On Mon, 15 Sep 2025 13:53:28 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/invoke/MethodHandles.java line 3449: > >> 3447: } >> 3448: // check if write access to final field allowed >> 3449: if (!field.isStatic() && isAccessible && allowedModes >> != TRUSTED) { > > I don't think we need this allowedModes special permission - I see no > scenario in which the core libraries implementation needs to perform such a > reflective operation. Thanks for pointing that out. It used to be required due to re-implementation of core reflection but you are right that it shouldn't be there now. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/25115#discussion_r2372776072
