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https://issues.apache.org/jira/browse/VELOCITY-952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17772341#comment-17772341
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Christopher Schultz commented on VELOCITY-952:
----------------------------------------------
I reported this as VELOCITY-968 and offered the following as a suggestion. I
don't know how the introspector works, so I'm just waving my hands, here:
"
Maybe
org.apache.velocity.util.introspection.MethodMap.getBestMatch(List<Method>,
Class[]) can choose a superclass method over a subclass method if they are
otherwise equivalent?
"
I've read the documentation for MethodOverrideUberspector.java and I think if
you just always use the most-superclass-or-superinterface method available,
many of these issues can be avoided without any additional overhead of
remembering the return-type of certain "get" invocations. This will also help
when Velocity wasn't responsible for performing the original access, for
example when the object is just dropped into the context by Java code and has a
runtime type different from the declared type in the code.
> Velocity is calling the "wrong" method
> --------------------------------------
>
> Key: VELOCITY-952
> URL: https://issues.apache.org/jira/browse/VELOCITY-952
> Project: Velocity
> Issue Type: Bug
> Components: Engine
> Affects Versions: 2.3
> Reporter: Thomas Mortagne
> Priority: Major
>
> OK, the title is maybe a bit harsh, but it catches the eyes :)
> At XWiki we recently started testing on Java 17 to see if there is any
> problem which leaded us to add things like {{--add-opens
> java.base/java.util=ALL-UNNAMED}} but Velocity happen to be the source of
> another problem related to the new module world.
> When doing something like {{$datetool.timeZone.getOffset(0)}} ($datetool
> being the org.apache.velocity.tools.generic.DateTool) we get the following
> error:
> {noformat}
> ...
> Caused by: java.lang.IllegalAccessException: class
> org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl cannot
> access class sun.util.calendar.ZoneInfo (in module java.base) because module
> java.base does not export sun.util.calendar to unnamed module @7ca16adc
> at
> java.base/jdk.internal.reflect.Reflection.newIllegalAccessException(Reflection.java:392)
> at
> java.base/java.lang.reflect.AccessibleObject.checkAccess(AccessibleObject.java:674)
> at java.base/java.lang.reflect.Method.invoke(Method.java:560)
> at
> org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:571)
> at
> org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:554)
> at
> org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:221)
> ... 199 more
> {noformat}
> The reason is that while the developer intent/expectation was to call
> "java.util.TimeZone#getOffset(0)" what Velocity really called from JVM point
> of view is "sun.util.calendar.ZoneInfo.getOffset(0)" directly.
> That's because Velocity is doing (I assume, since I did not check the exact
> code) the equivalent of:
> {noformat}
> java.util.TimeZone.getDefault().getClass().getMethod("getOffset",
> long.class).invoke(TimeZone.getDefault(), 0);
> {noformat}
> which is itself the equivalent of:
> {noformat}
> sun.util.calendar.ZoneInfo.class.getMethod("getOffset",
> long.class).invoke(TimeZone.getDefault(), 0);
> {noformat}
> I guess the only way to fix this would be to track down the lowest overridden
> Method (I agree, it might not always be easy to choose between two interfaces
> declaring a method with the same signature, but choosing the first one we
> find from the same hierarchy level is still better than nothing) and call
> that one instead. With the use case used as example in this issue, that would
> mean ending up doing the equivalent of:
> {noformat}
> java.util.TimeZone.class.getMethod("getOffset",
> long.class).invoke(TimeZone.getDefault(), 0);
> {noformat}
> which, from JVM point of view, is covered by the {{--add-opens
> java.base/java.util=ALL-UNNAMED}}.
> It would be a big change, but at least can't think of any retro-compatibility
> problem it might cause.
> One might be tempted to answer "just add {{--add-opens
> java.base/sun.util.calendar=ALL-UNNAMED}}" but it does not seem fair as this
> is not what the API that the script uses was exposing at all, you might need
> to document a different one for each JVM implementation (even if it's
> probably unlikely for this specific example) but more importantly you will
> potentially need quite a lot of those and will only discover it at runtime
> since it's not so easy to guess from an API in which you only know the public
> JVM classes since that's what you manipulate.
> I would be happy to work on this, but I wanted first ask what others think
> about this problem in general and the possible solutions I may have missed.
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