Filed: https://bugs.openjdk.java.net/browse/JDK-8260010 I have a potential fix ready, just trying to distill a minimal test case. /Claes On 2021-01-19 21:46, Claes Redestad wrote:

Hi,

yes, this seems like a bug introduced by JDK-8243469 where the previously thread-safe UTF8ZipCoder is now using a thread-unsafe decoder to calculate the normalized hash. I'll file a bug and take a look.

/Claes

On 2021-01-19 20:19, Vitaly Davidovich wrote:

...

Hi all,

I observed the following stacktrace when inspecting a JarFile's contents using a parallel stream (i.e. FJ pool):

Exception in thread "main" java.lang.IllegalStateException: java.lang.IllegalStateException: Current state = CODING_END, new state = FLUSHED

               at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native

Method)

               at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:64)

               at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

               at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)

               at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)

               at java.base/java.util.concurrent.ForkJoinTask.getThrowableException(ForkJoinTask.java:600)

               at java.base/java.util.concurrent.ForkJoinTask.reportException(ForkJoinTask.java:678)

               at java.base/java.util.concurrent.ForkJoinTask.invoke(ForkJoinTask.java:737)

               at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateParallel(ForEachOps.java:159)

               at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateParallel(ForEachOps.java:173)

               at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:233)

               at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)

               at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:575)

               at <stripped>.ClassVersions.conflicts(ClassVersions.java:703)

               at <stripped>.ClassVersions.check(ClassVersions.java:743)

               at <stripped>.ClassVersions.main(ClassVersions.java:839)

Caused by: java.lang.IllegalStateException: Current state = CODING_END, new state = FLUSHED

               at java.base/java.nio.charset.CharsetDecoder.throwIllegalStateException(CharsetDecoder.java:998)

               at java.base/java.nio.charset.CharsetDecoder.flush(CharsetDecoder.java:681)

               at java.base/java.nio.charset.CharsetDecoder.decode(CharsetDecoder.java:810)

               at java.base/java.util.zip.ZipCoder.normalizedHashDecode(ZipCoder.java:136)

               at java.base/java.util.zip.ZipCoder$UTF8ZipCoder.normalizedHash(ZipCoder.java:228)

               at java.base/java.util.zip.ZipFile$Source.initCEN(ZipFile.java:1527)

               at java.base/java.util.zip.ZipFile$Source.<init>(ZipFile.java:1249)

               at java.base/java.util.zip.ZipFile$Source.get(ZipFile.java:1211)

               at java.base/java.util.zip.ZipFile$CleanableResource.<init>(ZipFile.java:701)

               at java.base/java.util.zip.ZipFile.<init>(ZipFile.java:240)

               at java.base/java.util.zip.ZipFile.<init>(ZipFile.java:171)

               at java.base/java.util.jar.JarFile.<init>(JarFile.java:347)

               at java.base/java.util.jar.JarFile.<init>(JarFile.java:318)

               at java.base/java.util.jar.JarFile.<init>(JarFile.java:284)

               at <stripped>.ClassVersions.lookupJar(ClassVersions.java:665)

               at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)

               at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)

               at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)

               at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)

               at java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)

               at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)

               at java.base/java.util.stream.ForEachOps$ForEachTask.compute(ForEachOps.java:290)

               at java.base/java.util.concurrent.CountedCompleter.exec(CountedCompleter.java:746)

               at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)

               at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1016)

               at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1665)

               at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1598)

               at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)

(Note: I stripped off some package names to protect the innocent).

While investigating this a bit, I noticed some code that looks a bit suspect.  Namely:

    - ZipCoder has a singleton UTF8ZipCoder <https://github.com/openjdk/jdk/blob/05bcd67e6501f3824020edd1ab036c87888fa229/src/java.base/share/classes/java/util/zip/ZipCoder.java#L48>     instance it uses for UTF8 decoding.     - Source.get() creates a new Source <https://github.com/openjdk/jdk/blob/05bcd67e6501f3824020edd1ab036c87888fa229/src/java.base/share/classes/java/util/zip/ZipFile.java#L1225>     instance outside of any synchronization

The links above are to tip, but I think this code is the same in Java 15.

It seems possible that multiple threads can end up in Source.get(), new up a Source, and proceed to use the decoder of UTF8ZipCoder racily.  Per my understanding (and CharsetDecoder javadoc), CharsetDecoders are not threadsafe.

Any thoughts? Did I miss anything that would suggest the stacktrace above is due to something else entirely?

Thanks