Unsafe.defineAnonymousClass no longer exists in Java17!

[Attila Szegedi]

Hm… Are you using the Java module system? Or is this Wildfly otherwise messing with class loading? If loaded through the Java module system, Nashorn should have no problem accessing sun.misc.Unsafe as it properly declares <https://github.com/openjdk/nashorn/blob/main/src/org.openjdk.nashorn/share/classes/module-info.java#L145C5-L145C30> “require jdk.unsupported”. It does look like it might be somehow bundled in a WAR file though. Maybe that repackages it somehow?

If you’re intent on “emergency” modifying your copy of Nashorn, I'd add another catch clause at Context.java:338 <https://github.com/openjdk/nashorn/blob/main/src/org.openjdk.nashorn/share/classes/org/openjdk/nashorn/internal/runtime/Context.java#L338> like

catch(NoClassDefFoundError e) {
  initFailure = new RuntimeException(e);
  return null;
}

Although I’d be curious to know more about this error and circumstances under which it occurs. I’d be happy to try to debug it if you could give me a small reproducer. Alternatively, you could also run the java process with -verbose:class but it might not give us many clues.

Attila.

> On 2024. Jan 24., at 18:55, Luc Chapon <sxilderik at gmail.com> wrote:
> 
> This is my StackTrace.
> Since the line shown is the one trying to load a non existent method, I assumed that was the problem.
> The Exception seems to be NoClassDefFoundError instead…
> 
> The environement is Wildfly 30 / jdk 17
> 
> 18:31:00,119 ERROR [io.undertow.request] (default task-2) UT005023: Exception handling request to /HNS/HNSAdmin/query.pilot: java.lang.NoClassDefFoundError: sun/misc/Unsafe
> 	at deployment.HNS.war//org.openjdk.nashorn.internal.runtime.Context$AnonymousContextCodeInstaller.lambda$getDefineAnonymousClass$0(Context.java:330)
> 	at java.base/java.security.AccessController.doPrivileged(AccessController.java:318)
> 	at deployment.HNS.war//org.openjdk.nashorn.internal.runtime.Context$AnonymousContextCodeInstaller.getDefineAnonymousClass(Context.java:328)
> 	at deployment.HNS.war//org.openjdk.nashorn.internal.runtime.Context$AnonymousContextCodeInstaller.<clinit>(Context.java:317)
> 	at deployment.HNS.war//org.openjdk.nashorn.internal.runtime.Context.lambda$compile$9(Context.java:1506)
> 	at deployment.HNS.war//org.openjdk.nashorn.internal.runtime.ScriptEnvironment.useAnonymousClasses(ScriptEnvironment.java:491)
> 	at deployment.HNS.war//org.openjdk.nashorn.internal.runtime.Context.compile(Context.java:1506)
> 	at deployment.HNS.war//org.openjdk.nashorn.internal.runtime.Context.compileScript(Context.java:1451)
> 	at deployment.HNS.war//org.openjdk.nashorn.internal.runtime.Context.compileScript(Context.java:761)
> 	at deployment.HNS.war//org.openjdk.nashorn.api.scripting.NashornScriptEngine.compileImpl(NashornScriptEngine.java:528)
> 	at deployment.HNS.war//org.openjdk.nashorn.api.scripting.NashornScriptEngine.compileImpl(NashornScriptEngine.java:517)
> 	at deployment.HNS.war//org.openjdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:395)
> 	at deployment.HNS.war//org.openjdk.nashorn.api.scripting.NashornScriptEngine.eval(NashornScriptEngine.java:151)
> 	at java.scripting/javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:262)
> 
> 
> Le mer. 24 janv. 2024 à 18:20, Attila Szegedi <szegedia at gmail.com <mailto:szegedia at gmail.com>> a écrit :
>> Hi!
>> 
>> Are you experiencing this with Nashorn 15.4 from https://github.com/openjdk/nashorn? This issue is supposed to have been fixed since Nashorn 15.3 in this change https://github.com/openjdk/nashorn/pull/16 according to the changelog: https://github.com/openjdk/nashorn/blob/main/CHANGELOG.md
>> 
>> You say it fails, but it’s encased in a try-catch specifically for this reason. Can you give me a stack trace of how it fails?
>> 
>> Attila.
>> 
>> 
>>> On 2024. Jan 24., at 13:02, Luc Chapon <sxilderik at gmail.com <mailto:sxilderik at gmail.com>> wrote:
>>> 
>>> Hello all
>>> 
>>> First message here
>>> 
>>> We are facing a problem re Nashorn (latest) and java17
>>> 
>>> In Context.java, line 330, you try to get a handle to a no longer existent method, Unsafe.defineAnonymousClass
>>> 
>>> And fail of course.
>>> 
>>> I’m trying to rewrite this part for our own temporary urgent need according to this.
>>> 
>>> https://www.oracle.com/java/technologies/javase/17-relnote-issues.html
>>> core-libs
>>> ➜ <https://www.oracle.com/java/technologies/javase/17-relnote-issues.html#JDK-8243287> Removal of sun.misc.Unsafe::defineAnonymousClass
>>> sun.misc.Unsafe::defineAnonymousClass API has been removed in JDK 17. The API replacement is java.lang.invoke.MethodHandles.Lookup::defineHiddenClass and java.lang.invoke.MethodHandles.Lookup::defineHiddenClassWithClassData.
>>> 
>>> 
>>> Are you aware of the problem? Is there a fix already available?
>>> 
>>> Thank you!
>>> 
>>> Luc Chapon
>>> ChapsVision
>>> Suresnes, France
>>> 
>> 

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