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https://github.com/skuzzle/webapp-jul-to-slf4j
JDK Logger bridging for web applications
https://github.com/skuzzle/webapp-jul-to-slf4j
Last synced: 7 days ago
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JDK Logger bridging for web applications
- Host: GitHub
- URL: https://github.com/skuzzle/webapp-jul-to-slf4j
- Owner: skuzzle
- License: mit
- Created: 2015-06-19T11:09:04.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2015-06-19T15:28:40.000Z (over 9 years ago)
- Last Synced: 2024-10-08T13:09:12.114Z (28 days ago)
- Language: Java
- Size: 133 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
webapp-jul-to-slf4j
================
Little helper library allowing to enable JDK logger bridging during deployment time of a
web application. Please make sure you understand the implications of briding the JDK
logger that are described in the slf4j
[documentation](http://www.slf4j.org/legacy.html#jul-to-slf4j).
## Maven Dependency
```xml
de.skuzzle.slf4j
webapp-jul-to-slf4j
1.7.12
```
## Why?
The design of slf4j is all centered around deployment time flexibility. For most
slf4j extensions it is sufficient to place a certain jar into the class path and you are
done. However, for bridging the JDK logger to redirect it to slf4j, you currently have
to write additional setup code to have it run properly.
This extension is for use in web applications that are run in a Java EE 6 compliant
container. Those containers will query the `ServiceLoader` for service providers of the
type `ServletContainerInitializer`. This library implements such a listener to perform
the necessary steps for redirecting the JDK logger to slf4j.
## Usage
Simply put this library into the class path of your web application. As described above,
it will then automatically be recognized by the servlet container during startup.
Log messages sent to the JDK logger are only redirected to slf4j, if the respective logger
is enabled. Besides configuring the redirect to slf4j, this library will set the log level
of the JDK root logger to `ALL` in order to have it redirect all messages to slf4j.
## FAQ
### JDK logging bridge with tomcat and eclipse
When using slf4j's JDL bridge with a tomcat started from eclipse you are very likely to run into the following strange error:
```
java.lang.ClassCircularityError: java/util/logging/LogRecord
at org.slf4j.bridge.SLF4JBridgeHandler.getSLF4JLogger(SLF4JBridgeHandler.java:198)
at org.slf4j.bridge.SLF4JBridgeHandler.publish(SLF4JBridgeHandler.java:287)
at java.util.logging.Logger.log(Logger.java:731)
at java.util.logging.Logger.doLog(Logger.java:754)
at java.util.logging.Logger.logp(Logger.java:919)
at org.apache.juli.logging.DirectJDKLog.log(DirectJDKLog.java:183)
at org.apache.juli.logging.DirectJDKLog.debug(DirectJDKLog.java:106)
at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:369)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
at org.apache.catalina.startup.Catalina.start(Catalina.java:689)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:321)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:455)
```
This is due to the fact that tomcat, when being started using its startup script, replaces the JDK's LogManager for an own implementation. To achieve the same when running tomcat from eclipse, you need to edit its launch configuration and add the following line:
```
-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
```