[eclipse] At least one JAR was scanned for TLDs yet contained no TLDs

I keep getting this on tomcat 7.30 (eclipse juno)

At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.

Well I went at conf\logging.properties and turned all INFO to FINE and uncommented the line

# To see debug messages in TldLocationsCache, uncomment the following line:
org.apache.jasper.compiler.TldLocationsCache.level = FINE

And I still see At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging...

So what should I do to see those jars ?

Logs location :

The tomcat logs are in $CATALINA_HOME\logs\catalina.yyyy-mm-dd.log. Eclipse prints them in the console - if you want to have your console logged you must

In the servers tab, double-click on the Tomcat Server. You will get a screen called Overview. Click on "Open launch configuration". Click on the "Common" tab. Towards the bottom of the screen you can check the "File" checkbox and then specify a file that can be used to log your console (catalina.out) output. Finally, restart the Tomcat server.

apache-tomcat-8.0.33

If you want to enable debug logging in tomcat for TLD scanned jars then you have to change /conf/logging.properties file in tomcat directory.

uncomment the line :
org.apache.jasper.servlet.TldScanner.level = FINE

FINE level is for debug log.

This should work for normal tomcat.

If the tomcat is running under eclipse. Then you have to set the path of tomcat logging.properties in eclipse.

1. Open servers view in eclipse.Stop the server.Double click your tomcat server.
   This will open Overview window for the server.
2. Click on Open launch configuration.This will open another window.
3. Go to the Arguments tab(second tab).Go to VM arguments section.
4. paste this two line there :-
   -Djava.util.logging.config.file="{CATALINA_HOME}\conf\logging.properties"
   -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
   Here CATALINA_HOME is your PC's corresponding tomcat server directory.
5. Save the Changes.Restart the server.

Now the jar files that scanned for TLDs should show in the log.

For me I was getting the problem when deploying a geoserver WAR into tomcat 7

To fix it, I was on Java 7 and upgrading to Java 8.

This is running under a docker container. Tomcat 7.0.75 + Java 8 + Geos 2.10.2

(tomcat 7.0.32) I had problems to see debug messages althought was enabling TldLocationsCache row in tomcat/conf/logging.properties file. All I could see was a warning but not what libs were scanned. Changed every loglevel tried everything no luck. Then I went rogue debug mode (=remove one by one, clean install etc..) and finally found a reason.

My webapp had a customized tomcat/webapps/mywebapp/WEB-INF/classes/logging.properties file. I copied TldLocationsCache row to this file, finally I could see jars filenames.

# To see debug messages in TldLocationsCache, uncomment the following line: org.apache.jasper.compiler.TldLocationsCache.level = FINE

For anyone trying to get this working using the Sysdeo Eclipse Tomcat plugin, try the following steps (I used Sysdeo Tomcat Plugin 3.3.0, Eclipse Kepler, and Tomcat 7.0.53 to construct these steps):

1. Window --> Preferences --> Expand the Tomcat node in the tree --> JVM Settings
2. Under "Append to JVM Parameters", click the "Add" button.
3. In the "New Tomcat JVM parameter" popup, enter -Djava.util.logging.config.file="{TOMCAT_HOME}\conf\logging.properties", where {TOMCAT_HOME} is the path to your Tomcat directory (example: C:\Tomcat\apache-tomcat-7.0.53\conf\logging.properties). Click OK.
4. Under "Append to JVM Parameters", click the "Add" button again.
5. In the "New Tomcat JVM parameter" popup, enter -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager. Click OK.
6. Click OK in the Preferences window.
7. Make the adjustments to the {TOMCAT_HOME}\conf\logging.properties file as specified in the question above.
8. The next time you start Tomcat in Eclipse, you should see the scanned .jars listed in the Eclipse Console instead of the "Enable debug logging for this logger" message. The information should also be logged in {TOMCAT_HOME}\logs\catalina.yyyy-mm-dd.log.

(tomcat 8.0.28) Above method did not work for me. This is what worked:

1. Add this line to the end of your {CATALINA-HOME}/conf/logging.properties:

   org.apache.jasper.level = FINEST
   

2. Shut down the server (if started).

3. Open console and run (in case of Windows):

   %CATALINA_HOME%\bin\catalina.bat run
   

4. Enjoy logs, e.g. (again, for Windows):

   {CATALINA-HOME}/logs/catalina.2015-12-28.log
   

I gave up on integrating this with Eclipse launch configuration so be aware that this works only from console, launching the server from Eclipse won't produce additional log messages.