How to fix JSP compiler warning one JAR was scanned for TLDs yet contained no TLDs

Question

When starting the application or compiling JSP via ant  Tomcat 7 Jasper complains about superfluous or misplaced JAR file  I got below message     compile-jsp        jasper  Jul 31  2012 7 15 15 PM org apache jasper compiler TldLocationsCache tldScanJar     jasper  INFO  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     how to Skipping unneeded JARs during scanning can improve startup time and JSP compilation time in tomcat   how to enable better output

User · Answer

The warning comes up because Tomcat scans all Jars for TLDs (Tagging Library Definitions).

Step1: To see which JARs are throwing up this warning, insert he following line to tomcat/conf/logging.properties

org.apache.jasper.servlet.TldScanner.level = FINE

Now you should be able to see warnings with a detail of which JARs are causing the intial warning

Step2 Since skipping unneeded JARs during scanning can improve startup time and JSP compilation time, we will skip un-needed JARS in the catalina.properties file. You have two options here -

List all the JARs under the tomcat.util.scan.StandardJarScanFilter.jarsToSkip. But this can get cumbersome if you have a lot jars or if the jars keep changing.
Alternatively, Insert tomcat.util.scan.StandardJarScanFilter.jarsToSkip=* to skip all the jars

You should now not see the above warnings and if you have a considerably large application, it should save you significant time in deploying an application.

Note: Tested in Tomcat8

User · Answer

The error message states which logger it is using  so set that logger  level    jasper  Jul 31  2012 7 15 15 PM org apache jasper compiler TldLocationsCache tldScanJar   So the logger is org apache jasper compiler TldLocationsCache   In your logging properties file  add this line   org apache jasper compiler TldLocationsCache level   FINE

User · Answer

Uncomment this line  in  conf logging properties   org apache jasper compiler TldLocationsCache level   FINE   Work s for me in tomcat 7 0 53

User · Answer

For Tomcat 8  I had to add the following line to tomcat conf logging properties for the jars scanned by Tomcat to show up in the logs   org apache jasper servlet TldScanner level   FINE

User · Answer

Tomcat 8 5  Inside catalina properties  located in the  conf directory set   tomcat util scan StandardJarScanFilter jarsToSkip    jar   Or go into context xml  located in Tomcat s  conf directory and add    lt JarScanner scanClassPath  false   gt

User · Answer

The above solution did not work for me  Instead I simply removed the hash    from the last line of the logging properties file  to make it work     To see debug messages in TldLocationsCache  uncomment the following line  org apache jasper compiler TldLocationsCache level   FINE   The next step is to add the jars that Tomcat 7 is looking for in catalina properties files just after the following line   org apache catalina startup TldConfig jarsToSkip

User · Answer

For Tomcat 8  I had to add the following line to catalina properties for preventing jars scanned by Tomcat   tomcat util scan StandardJarScanFilter jarsToSkip jsp-api jar servlet-api jar

User · Answer

If the extra entries in the log bother you but an extra second of start-up time doesn t  just add this to your logging properties and forget about it   org apache jasper servlet TldScanner level   WARNING

User · Answer

None of the above worked for me  tomcat 7 0 62     As Sensei Shoh notes see the class above the message and add this to logging properties  My logs were   Jan 18  2016 8 44 21 PM org apache catalina startup TldConfig execute INFO  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    so I added  org apache catalina startup TldConfig level   FINE   in conf logging properties  After that I got so many  offending  files that I did not bother skipping them  and also reverted to normal logging

User · Answer

If it helps anyone  I just appended the contents of the below output file to the existing org apache catalina startup TldConfig jarsToSkip  entry    Note that  var log tomcat7 catalina out is the location of your tomcat log   egrep  No TLD files were found in   file           var log tomcat7 catalina out -o   egrep         jar  -o   sort   uniq   sed -e  s  jar  jar    g   gt  skips txt   Hope that helps

[logging] How to fix JSP compiler warning: one JAR was scanned for TLDs yet contained no TLDs?

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