On Mon, 11 Apr 2022 06:41:54 GMT, Alan Bateman <al...@openjdk.org> wrote:
>> The tests serviceability/jvmti/RedefineClasses start failing in loom-repo >> with CNFE like "java.lang.NoClassDefFoundError: >> jdk/test/lib/compiler/InMemoryJavaCompiler" >> >> It is not a loom specific bug, it might happen in jdk/jdk also. >> >> The workaround is to build some classes explicitly. The fix was implemented >> in repo-loom in Nov 2021 and there was no such failure after the fix in the >> loom repo. >> >> Also fix inlcudes some text refactoring to make push from loom smaller. > > The issue with RedefineClassTest throwing NoClassDefFoundError: > jdk/test/lib/InMemoryJavaCompiler seems to go back to 2016 at least. We've > had issues in other areas in the past that stemmed from implicit compilation > so I assume this is what is suspected here too. > > In the loom repo, two of the existing RedefineClasss* classes have an > explicit `@compile` because the updated tests needed to be compiled with > `--enable-preview`. I would be surprised if this caused an issue but maybe it > creates an issue with concurrent test execution when tests that depend on > implicit compilation are running at the same time (in another agentvm) but > doing explicit compilation? I wonder if creating a TEST.properties with > `exclusiveAccess.dirs=.` would help this area. > @AlanBateman adding the explicit compile commands to add `--enable-preview` > is exactly what causes the problem. By compiling that individual file first > it also compiled some testlib dependencies but puts the classes in a > different place. When another class is later compiled, the compilation path > includes that destination and so compilation succeeds, but at runtime the > path is different and we get the NCDFE. This is the analysis that Alex did in > a similar issue - see his comment in JBS. Adding `--enable-preview` did not intentionally mean to introduce implicit compilation but it looks like we'll have to re-visit the ordering (as @alexmenkov suggests) in the loom repo. ------------- PR: https://git.openjdk.java.net/jdk/pull/8170
