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https://issues.apache.org/jira/browse/MANTRUN-200?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16138712#comment-16138712
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Guillaume Boué commented on MANTRUN-200:
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[~rfscholte] Yes, the parent used by ServiceLoader to delegate is returned by
{{getParent()}}, and this is {{null}}. Just considering modules, it means only
services present in modules loaded by the bootstrap classloader are found. I
think Nashorn is loaded with the system classloader in Java 9 (and was
previously loaded with bootstrap classloader). So from what I gathered, passing
the system classloader, instead of {{null}}, in {{world.newRealm( realmId, null
)}} would solve this Jira issue, meaning the Nashorn implementation would be
found (I tested this previously and it really solves it).
But I'm afraid it would just hide another issue: a module loaded by the Maven
core extension classloader still would not be found. For that, I believe you
would need to pass Core Ext classloader as parent in {{world.newRealm( realmId,
null )}}, or even pass whatever {{parent}} was passed to {{createRealm}} in
{{DefaultClassRealmManager}}, but I tested that this has bad consequences for
plugins using the Site Plugin. The problem was that the search for a given
class would now delegate to the parent first and then plugin classloader. In
the case of the Site Plugin, the parent would be the Site Plugin's realm, and
this would mean that it is the classes loaded by maven-site that are found
before the ones of the plugin itself...and this quickly turned into version
conflicts and ClassNotFoundException when the plugin overrides a dependency...
> Scriptdef tasks fail to load when running on Java9
> --------------------------------------------------
>
> Key: MANTRUN-200
> URL: https://issues.apache.org/jira/browse/MANTRUN-200
> Project: Maven Antrun Plugin
> Issue Type: Bug
> Affects Versions: 1.8
> Reporter: Dan Berindei
>
> I have a Maven project using maven-antrun-plugin:
> {code}
> <?xml version='1.0' encoding='UTF-8'?>
> <project>
> <modelVersion>4.0.0</modelVersion>
> <artifactId>my-test-app</artifactId>
> <groupId>my-test-group</groupId>
> <version>1.0-SNAPSHOT</version>
> <build>
> <plugins>
> <plugin>
> <groupId>org.apache.maven.plugins</groupId>
> <artifactId>maven-antrun-plugin</artifactId>
> <version>1.8</version>
> <executions>
> <execution>
> <id>compile</id>
> <phase>compile</phase>
> <configuration>
> <target>
> <ant antfile="build.xml" inheritRefs="true">
> <target name="all"/>
> </ant>
> </target>
> </configuration>
> <goals>
> <goal>run</goal>
> </goals>
> </execution>
> </executions>
> </plugin>
> </plugins>
> </build>
> </project>
> {code}
> The Ant build file uses a script:
> {code}
> <?xml version='1.0' encoding='UTF-8'?>
> <project name="scriptdef-test-build">
> <scriptdef name="test-script" language="javascript">
> <![CDATA[
> var System = Java.type('java.lang.System');
> System.out.println("Working!");
> ]]>
> </scriptdef>
> <target name="all">
> <test-script/>
> </target>
> </project>
> {code}
> On Java 8 it works, but on Java 9 (9-ea+162) it can't find the script engine:
> {noformat}
> org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute
> goal org.apache.maven.plugins:maven-antrun-plugin:1.8:run (compile) on
> project my-test-app: An Ant BuildException has occured: The following error
> occurred while executing this line:
> /home/dan/scriptdef-test/build.xml:10: Unable to create javax script engine
> for javascript
> around Ant part ...<ant antfile="build.xml" inheritRefs="true">... @ 4:47 in
> /home/dan/scriptdef-test/target/antrun/build-main.xml
> ...
> Caused by: /home/dan/scriptdef-test/build.xml:10: Unable to create javax
> script engine for javascript
> at
> org.apache.tools.ant.util.optional.JavaxScriptRunner.evaluateScript(JavaxScriptRunner.java:84)
> at
> org.apache.tools.ant.util.optional.JavaxScriptRunner.executeScript(JavaxScriptRunner.java:67)
> at
> org.apache.tools.ant.taskdefs.optional.script.ScriptDef.executeScript(ScriptDef.java:350)
> at
> org.apache.tools.ant.taskdefs.optional.script.ScriptDefBase.execute(ScriptDefBase.java:50)
> at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
> at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native
> Method)
> at
> java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
> at
> java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.base/java.lang.reflect.Method.invoke(Method.java:547)
> 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:435)
> at org.apache.tools.ant.Target.performTasks(Target.java:456)
> at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1393)
> at
> org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecutor.java:38)
> at org.apache.tools.ant.Project.executeTargets(Project.java:1248)
> at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:441)
> ... 34 more
> {noformat}
> I have attached a debugger and I saw that the {{ScriptEngineManager}} used by
> {{JavaxScriptRunner}} doesn't have any script engines, because the service
> loader it uses doesn't find any {{ScriptEngineFactory}} implementations. I
> have tried {{\--add-modules jdk.scripting.nashorn}} and {{\--add-opens
> jdk.scripting.nashorn/jdk.nashorn.api.scripting=ALL-UNNAMED}}, but neither
> helped.
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