What does "INFO: TLD skipped. URI is already defined" mean?

Question

When running my JSF 2 application in eclipse I am getting several info logs that TLD was skipped because it's already defined as follows:

Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://www.springframework.org/tags/form is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://www.springframework.org/tags is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jstl/core_rt is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jstl/core is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jsp/jstl/core is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jstl/fmt_rt is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jstl/fmt is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jsp/jstl/fmt is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jsp/jstl/functions is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://jakarta.apache.org/taglibs/standard/permittedTaglibs is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://jakarta.apache.org/taglibs/standard/scriptfree is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jstl/sql_rt is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jstl/sql is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jsp/jstl/sql is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jstl/xml_rt is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jstl/xml is already defined
Jan 3, 2012 7:24:45 PM org.apache.catalina.startup.TaglibUriRule body
INFO: TLD skipped. URI: http://java.sun.com/jsp/jstl/xml is already defined

I am curious to know, what does this log mean?

Answer 1

This means that you have duplicate TLD files in your webapp's runtime classpath. As TLDs are normally contained in the library JAR files, this in turn means that you have duplicate JAR files in your webapp's runtime classpath.

Assuming that you haven't touched appserver's /lib folder nor the JDK's /lib folders, then those duplicates are in the /WEB-INF/lib folder of the WAR build. Cleanup it.