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https://issues.apache.org/jira/browse/LOG4J2-2025?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16591836#comment-16591836
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ASF GitHub Bot commented on LOG4J2-2025:
----------------------------------------
Github user rgoers commented on a diff in the pull request:
https://github.com/apache/logging-log4j2/pull/213#discussion_r212672416
--- Diff: log4j-jul/src/site/markdown/index.md ---
@@ -74,3 +74,29 @@ Java Level | Log4j Level
[`FINER`](http://docs.oracle.com/javase/6/docs/api/java/util/logging/Level.html#FINER)
| `TRACE`
[`FINEST`](http://docs.oracle.com/javase/6/docs/api/java/util/logging/Level.html#FINEST)
| [`FINEST`](apidocs/org/apache/logging/log4j/jul/LevelTranslator.html#FINEST)
[`ALL`](http://docs.oracle.com/javase/6/docs/api/java/util/logging/Level.html#ALL)
| `ALL`
+
+
+# Log4j JDK Logging Bridge
+
+The LogManager is not always useable because you have to set a JVM wide
effective system
+property - e.g. in web servers this is not possible if you are not the
administrator.
+
+The
[`Log4jBridgeHandler`](apidocs/org/apache/logging/log4j/jul/Log4jBridgeHandler.html)
is an
+alternative that can be declaratively used via `logging.properties`.
+It is less performant than the LogManager but still okay to use.
--- End diff --
This should also note that logging methods are subject to filtering by BOTH
java.util.logging and log4j 2.
> Support Tomcat JULI's per-webapp JUL logging by implementing
> java.util.logging.Handler
> --------------------------------------------------------------------------------------
>
> Key: LOG4J2-2025
> URL: https://issues.apache.org/jira/browse/LOG4J2-2025
> Project: Log4j 2
> Issue Type: Improvement
> Components: JUL adapter
> Affects Versions: 2.8.2
> Environment: Tomcat 8.5.20, Oracle Java 1.8.0_144
> Reporter: Ibrahim M. Ghazal
> Assignee: Ralph Goers
> Priority: Minor
> Fix For: 2.11.2
>
>
> On most servlet containers, the only way to redirect JUL calls to Log4j is by
> setting the
> {{java.util.logging.manager=org.apache.logging.log4j.jul.LogManager}} system
> property *globally*. This often breaks the native logging of the container,
> and could also break other apps on the same container do not use Log4j 2.
> This also requires changing the container's settings and cannot be expressed
> in the app itself.
> Another approach (used by slf4j) is to implement
> {{java.util.logging.Handler}} and then install this handler at the root
> logger, either programmatically by calling
> {{LogManager.getLogManager().getLogger("").addHandler(...)}} or by changing
> logging.properties at the JRE level. This also breaks the container's native
> logging and other apps, but in different ways than LogManager. I do not
> advocate this approach, but it's useful to know about it as a background for
> this feature request.
> (tl;dr: It's impossible to reliably redirect JUL from a webapp without
> creating a mess).
> Thankfully, Tomcat has a solution for this: Tomcat
> [JULI|https://tomcat.apache.org/tomcat-8.5-doc/logging.html] allows
> per-webapp configuration by adding a {{WEB-INF/classes/logging.properties}}
> file with {{handlers=some.custom.Handler}} inside it. This will redirect JUL
> calls from this webapp (and this webapp only) to that handler, and that
> handler then can redirect to Log4j.
> In short: Add a {{java.util.logging.Handler}} implementation that redirects
> to Log4j so that webapps can use Tomcat's per-webapp configuration and avoid
> the JUL mess.
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