[jira] [Commented] (KARAF-6385) WARNING: sun.reflect.Reflection.getCallerClass is not supported. This will impact performance.

["Jean-Baptiste Onofré (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KARAF-6385?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16913129#comment-16913129 ] 

Jean-Baptiste Onofré commented on KARAF-6385:
---------------------------------------------

By the way, Karaf 4.2.x also run with Java 11 and 12. Let me check on pax-logging.

> WARNING: sun.reflect.Reflection.getCallerClass is not supported. This will impact performance.
> ----------------------------------------------------------------------------------------------
>
>                 Key: KARAF-6385
>                 URL: https://issues.apache.org/jira/browse/KARAF-6385
>             Project: Karaf
>          Issue Type: Bug
>          Components: karaf
>         Environment: Karaf 4.3.0 + Java 11
>            Reporter: Xtra Coder
>            Assignee: Jean-Baptiste Onofré
>            Priority: Major
>
> I've tried using Karaf 4.3.0 built from sources (to fix another issue) and on Java 11 now am always getting following message in console: 
> {code:java}
> WARNING: sun.reflect.Reflection.getCallerClass is not supported. This will impact performance.
> {code}
> It appears it comes from log4j (specifically [this line|https://github.com/apache/logging-log4j2/blob/master/log4j-api/src/main/java/org/apache/logging/log4j/util/StackLocator.java#L78]) and is raised because on Java 11 reflection from Java8 does not work and "org.ops4j.pax.logging" does not include java9-compatible classes most probably because of [this issue|https://github.com/bndtools/bnd/issues/2227].
> This message does not appear in Karaf 4.2.6 and after some debugging I see this is happening because in 4.2.6 version of "org.ops4j.pax.logging" is 1.10.2 and code goes through [this line|https://github.com/ops4j/org.ops4j.pax.logging/blob/paxlogging-1.10.x/pax-logging-log4j2/src/main/java/org/ops4j/pax/logging/log4j2/internal/PaxAppenderProxy.java#L61]: 
>  _getServices() returns null and therefore event.getLocationInformation() is not invoked_
> {code:java}
>     public void doAppend( PaxLoggingEvent event )
>     {
>         if (count != getTrackingCount()) {
>             count = getTrackingCount();
>             appenders = getServices();
>         }
>         if (appenders != null && appenders.length > 0) {
>             // Bug in Karaf, as it expects the source to be available
>             event.getLocationInformation();
>             for (Object appender : appenders) {
>                 ((PaxAppender) appender).doAppend(event);
>             }
>         }
>     }
> {code}
> In "org.ops4j.pax.logging" v1.11.0 (included in 4.3.0) code goes through [this line|https://github.com/ops4j/org.ops4j.pax.logging/blob/master/pax-logging-api/src/main/java/org/ops4j/pax/logging/spi/support/PaxAppenderProxy.java#L67]: 
>  _because getServices(<empty array>) returns that same empty array, code falls into 'if' with that empty array and event.getLocationInformation(); is called (what throws the subject WARNING), whereas its output is not used because list of appenders is empty - no event.getLocationInformation() == no WARNING_
> {code:java}
>         @Override
>     public void doAppend(PaxLoggingEvent event) {
>         if (count != getTrackingCount()) {
>             count = getTrackingCount();
>             appenders = getServices(new PaxAppender[0]);
>         }
>         if (appenders != null) {
>             // Bug in Karaf, as it expects the source to be available
>             event.getLocationInformation();
>             for (PaxAppender appender : appenders) {
>                 appender.doAppend(event);
>             }
>         }
>     }
> {code}
> So ... it seems it is bug in "org.ops4j.pax.logging" v1.11.0 and it is to early to include it into Karaf.
>  



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