Update: They changed it in Java 5. ClassGen.setMajor(49) + ClassGen.setMinor(0) works.
On Fri, 4 Feb 2022 at 15:26, Stefan Reich < stefan.reich.maker.of....@googlemail.com> wrote: > Mystery solved, ladies and gentlemen... > > It was... > > the byte code version. BCEL outputs version 45.3 by default (JDK 1.1). > There were multiple changes to the class file format spec since then. > > Specifically, they must have allowed ldc to load .class objects directly > at some point after JDK 1.1. In fact, I distinctly remember the > Class.forName shenanigans that javac produced back then instead of the > direct ldc. > > Apparently the Java verifier is so strict it judges the class file > according to its version number and disallows the new version of ldc in a > class file written for JDK 1.1. > > BCEL doesn't check for this though and outputs a broken class file. > Changing this might be a good idea. > > Unfortunately I couldn't find documentation on when the byte code spec > change happened. Does anyone know? > > Neither did I find anything in the HotSpot verifier sources > <https://github.com/openjdk/jdk/blob/master/src/hotspot/share/classfile/verifier.cpp> > which is odd to me. No mention of a JDK version there. Only in > clasfileparser.cpp > <https://github.com/openjdk/jdk/blob/master/src/hotspot/share/classfile/classFileParser.cpp> > but didn't find the issue in question there either. I'm by no means an > expert in the JDK C++ source though. > > Cheers > Stefan > > On Thu, 3 Feb 2022 at 08:32, Romain Manni-Bucau <rmannibu...@gmail.com> > wrote: > >> Hi, >> >> Maybe a bit ot of topic but did you check with asm (using classreader for >> ex) if it is readable for it? Javap in verbose mode is hard to read >> humanly >> (and not verbosel does not mean much) so an issue can still be hidden. >> >> Romain Manni-Bucau >> @rmannibucau <https://twitter.com/rmannibucau> | Blog >> <https://rmannibucau.metawerx.net/> | Old Blog >> <http://rmannibucau.wordpress.com> | Github < >> https://github.com/rmannibucau> | >> LinkedIn <https://www.linkedin.com/in/rmannibucau> | Book >> < >> https://www.packtpub.com/application-development/java-ee-8-high-performance >> > >> >> >> Le jeu. 3 févr. 2022 à 01:42, Stefan Reich >> <stefan.reich.maker.of....@googlemail.com.invalid> a écrit : >> >> > I'm mainly curious how it's possible that everything looks completely >> > normal in javap (checked a dozen times), but the class verifier >> complains >> > anyway? Something has to be different. Is there a way to dig deeper >> into a >> > class file? >> > >> > Greetings >> > >> > On Wed, 2 Feb 2022 at 23:14, Stefan Reich < >> > stefan.reich.maker.of....@googlemail.com> wrote: >> > >> > > Hmm, no change with latest version. >> > > >> > > I did "git clone https://github.com/apache/commons-bcel.git"; and "mvn >> > > package". >> > > >> > > stefan@lenovo-ThinkPad-X220:~/dev/classreftest$ javac -cp >> > > bcel-6.6.0-SNAPSHOT.jar MakeBadClassFile.java >> > > stefan@lenovo-ThinkPad-X220:~/dev/classreftest$ java -cp >> > > bcel-6.6.0-SNAPSHOT.jar:. MakeBadClassFile >> > > Now please try: java BadClassFile >> > > stefan@lenovo-ThinkPad-X220:~/dev/classreftest$ java BadClassFile >> > > Error: Unable to initialize main class BadClassFile >> > > Caused by: java.lang.VerifyError: (class: BadClassFile, method: main >> > > signature: ([Ljava/lang/String;)V) Illegal type in constant pool >> > > stefan@lenovo-ThinkPad-X220:~/dev/classreftest$ >> > > >> > > On Wed, 2 Feb 2022 at 22:59, Gary Gregory <garydgreg...@gmail.com> >> > wrote: >> > > >> > >> You should try the latest from git master. >> > >> >> > >> Gary >> > >> >> > >> On Wed, Feb 2, 2022, 15:41 Stefan Reich >> > >> <stefan.reich.maker.of....@googlemail.com.invalid> wrote: >> > >> >> > >> > Hi again, >> > >> > >> > >> > actual problem this time... >> > >> > >> > >> > I think I am doing everything right... Decompilation in javap -v >> looks >> > >> > just like it should. But I get a VerifyError... I'm using JDK 17. >> Full >> > >> > program attached. Please advice, thank you :) >> > >> > >> > >> > # javac -cp bcel-6.5.0.jar MakeBadClassFile.java >> > >> > # java -cp bcel-6.5.0.jar:. MakeBadClassFile >> > >> > # java BadClassFile >> > >> > Error: Unable to initialize main class BadClassFile >> > >> > Caused by: java.lang.VerifyError: (class: BadClassFile, method: >> main >> > >> > signature: ([Ljava/lang/String;)V) Illegal type in constant pool >> > >> > >> > >> > >> > >> > >> --------------------------------------------------------------------- >> > >> > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org >> > >> > For additional commands, e-mail: dev-h...@commons.apache.org >> > >> >> > > >> > > >> > > >
