On Tue, 23 Sep 2025 18:03:54 GMT, Alan Bateman <[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 > > Alan Bateman has updated the pull request incrementally with two additional > commits since the last revision: > > - Review feedback > - Change ciField::initialize_from to use is_mutable_static_final, suggested > by Vladimir Ivanov test/hotspot/jtreg/runtime/jni/mutateFinals/MutateFinalsTest.java line 109: > 107: String instanceMethod = list1.get(rand.nextInt(list1.size())); > 108: String staticMethod = list2.get(rand.nextInt(list2.size())); > 109: return Stream.of(instanceMethod, staticMethod); * What is the rationale for choosing a random `pairOf(instanceMutator, classMutator)`? * Does "instance mutator gets followed by a class mutator" have any particular importance for the tests they are used? I was looking at this argument supplier and thinking of `Collections.shuffle()` over a list containing all method names, preferably, multiple times. test/hotspot/jtreg/runtime/jni/mutateFinals/MutateFinalsTest.java line 142: > 140: private OutputAnalyzer test(String methodName, String... vmopts) > throws Exception { > 141: Stream<String> s1 = Stream.of( > 142: "-Djava.library.path=" + javaLibraryPath, `javaLibraryPath` is only used here. You can consider inlining `System::getProperty` here and saving yourself from lines 51..56. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/25115#discussion_r2382369054 PR Review Comment: https://git.openjdk.org/jdk/pull/25115#discussion_r2382360896
