Does Nashorn (org.openjdk.nashorn) have any support for Java 17?

[Attila Szegedi]

Hi Greg,

that’s a consequence of Java 17 removing the Unsafe.defineAnonymousClass method. Unfortunately, we don’t have an ideal replacement for it yet. MethodHandles.Lookup.defineHiddenClass is supposed to be a publicly supported replacement, but it hides the generated classes from stack traces, and that makes Nashorn incorrectly report exception stack traces, since we use this method to emit code compiled from scripts.

There’s been some discussion about this[0] and the JDK team at Oracle is aware that we’d need a better replacement API but there’s not one available yet :-(

We use Unsafe.defineAnonymousClass for Nashorn’s lazy compilation feature, where it compiles every function independently just before it is executed for the first time. This is in contrast to eager compilation, where the whole script is compiled when it is loaded. Lazy compilation is the default.

One thing you can do right now is try to somehow pass “false” as the value of the “lazy.compilation” system property to turn off lazy compilation.

I’ve been working on a branch that’ll handle the problem gracefully and default to eager compilation if Unsafe.defineAnonymousClass is not present in the Java runtime. I’ll probably make a release soon with this fix.

Hope this helps,
  Attila.

[0] https://mail.openjdk.java.net/pipermail/core-libs-dev/2021-May/077347.html


> On 2021. Jun 28., at 18:24, Greg Watts <gwatts at us.ibm.com> wrote:
> 
> 
> Dear Nashorn development team,
> 
> I am trying to run an ANT build of our product using
> nashorn-core:15.1.1.jar with Java 17 (pre-release - build 27) and I get:
> 
> BUILD FAILED
> java.lang.ExceptionInInitializerError
>    at
> org.openjdk.nashorn.internal.runtime.Context.compile(Context.java:1509)
>    at
> org.openjdk.nashorn.internal.runtime.Context.compileScript(Context.java:1449)
>    at
> org.openjdk.nashorn.internal.runtime.Context.compileScript(Context.java:759)
>    at
> org.openjdk.nashorn.api.scripting.NashornScriptEngine.compileImpl(NashornScriptEngine.java:528)
>    at
> org.openjdk.nashorn.api.scripting.NashornScriptEngine.compileImpl(NashornScriptEngine.java:517)
>    at
> org.openjdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:395)
>    at
> org.openjdk.nashorn.api.scripting.NashornScriptEngine.eval(NashornScriptEngine.java:151)
>    at
> java.scripting/javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:262)
>    at
> java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native
> Method)
>    at
> java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
>    at
> java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>    at java.base/java.lang.reflect.Method.invoke(Method.java:568)
>    at org.apache.tools.ant.util.ReflectUtil.invoke(ReflectUtil.java:108)
>    at
> org.apache.tools.ant.util.ReflectWrapper.invoke(ReflectWrapper.java:81)
>    at
> org.apache.tools.ant.util.optional.JavaxScriptRunner.evaluateScript(JavaxScriptRunner.java:103)
>    at
> org.apache.tools.ant.util.optional.JavaxScriptRunner.executeScript(JavaxScriptRunner.java:67)
>    at
> org.apache.tools.ant.taskdefs.optional.Script.execute(Script.java:52)
>    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
>    at jdk.internal.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
>    at
> java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>    at java.base/java.lang.reflect.Method.invoke(Method.java:568)
>    at
> org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
>    at org.apache.tools.ant.Task.perform(Task.java:348)
>    at org.apache.tools.ant.Target.execute(Target.java:392)
>    at org.apache.tools.ant.Target.performTasks(Target.java:413)
>    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
>    at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
>    at
> org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
>    at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
>    at org.apache.tools.ant.Main.runBuild(Main.java:811)
>    at org.apache.tools.ant.Main.startAnt(Main.java:217)
>    at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
>    at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
> Caused by: java.lang.RuntimeException: java.lang.NoSuchMethodException: no
> such method:
> sun.misc.Unsafe.defineAnonymousClass(Class,byte[],Object[])Class/invokeVirtual
>    at org.openjdk.nashorn.internal.runtime.Context
> $AnonymousContextCodeInstaller.lambda$getDefineAnonymousClass
> $0(Context.java:335)
>    at
> java.base/java.security.AccessController.doPrivileged(AccessController.java:318)
>    at org.openjdk.nashorn.internal.runtime.Context
> $AnonymousContextCodeInstaller.getDefineAnonymousClass(Context.java:327)
>    at org.openjdk.nashorn.internal.runtime.Context
> $AnonymousContextCodeInstaller.<clinit>(Context.java:317)
>    ... 33 more
> Caused by: java.lang.NoSuchMethodException: no such method:
> sun.misc.Unsafe.defineAnonymousClass(Class,byte[],Object[])Class/invokeVirtual
>    at
> java.base/java.lang.invoke.MemberName.makeAccessException(MemberName.java:976)
>    at java.base/java.lang.invoke.MemberName
> $Factory.resolveOrFail(MemberName.java:1117)
>    at java.base/java.lang.invoke.MethodHandles
> $Lookup.resolveOrFail(MethodHandles.java:3643)
>    at java.base/java.lang.invoke.MethodHandles
> $Lookup.findVirtual(MethodHandles.java:2680)
>    at org.openjdk.nashorn.internal.runtime.Context
> $AnonymousContextCodeInstaller.lambda$getDefineAnonymousClass
> $0(Context.java:329)
>    ... 36 more
> Caused by: java.lang.NoSuchMethodError: 'java.lang.Class
> sun.misc.Unsafe.defineAnonymousClass(java.lang.Class, byte[],
> java.lang.Object[])'
>    at java.base/java.lang.invoke.MethodHandleNatives.resolve(Native
> Method)
>    at java.base/java.lang.invoke.MemberName
> $Factory.resolve(MemberName.java:1085)
>    at java.base/java.lang.invoke.MemberName
> $Factory.resolveOrFail(MemberName.java:1114)
>    ... 39 more
> 
> 
> So I was curious to know please if Nashorn will be supported in Java 17,
> and if so, when you might anticipate that to be released (ballpark
> estimate)?
> 
> 
> Greg Watts
> WebSphere Zombie Apocalypse Team
> External: 507-253-8901
> email: gwatts at us.ibm.com
> 
> "Take risks:  if you win, you will be happy; if you lose, you will be wise"
> - Unknown