Page History

...

This page discusses the various ways you see Class Not Found errors or very similar errors. It is strongly advised you read the following topics:

• Wiki MarkupClassloader HOWTO pages: \[http://tomcat.apache.org/tomcat-4.1-doc/class-loader-howto.html Tomcat 4.1\], \[http://tomcat.apache.org/tomcat-5.5-doc/class-loader-howto.html Tomcat 5.5\], \[http://tomcat.apache.org/tomcat-6.0-doc/class-loader-howto.html Tomcat 6.0\].
• Wiki Markup\[http://marc.theaimsgroup.com/?t=104317529200004&r=1&w=2 Don't\] \[http://marc.theaimsgroup.com/?t=104380440100003&r=1&w=2 use\] \[http://marc.theaimsgroup.com/?t=96947656900002&r=1&w=2 packageless\] \[http://marc.theaimsgroup.com/?t=104491020100002&r=1&w=2 classes\] \[http://marc.theaimsgroup.com/?t=104265576200003&r=1&w=2 and\] \[http://marc.theaimsgroup.com/?t=104249748300001&r=1&w=2 declare\] \[http://marc.theaimsgroup.com/?t=102996950100003&r=1&w=2 all\] \[http://marc.theaimsgroup.com/?t=102922189400001&r=1&w=2 imported classes\]!
• Wiki Markup\[http://marc.theaimsgroup.com/?l=tomcat-user&m=103843452413727&w=2 Another answer to a classloader issue\] \\
  

If you get a NoClassDefFoundError exception, the root cause might be the same as for a ClassNotFound exception.

Questions

...

1. \[#Q1 Why is jsp:useBean is not working?\]unmigrated-wiki-markup
2. \[#Q2 Why do I get java.lang.NoClassDefFoundError: javax/servlet/Filter?\]unmigrated-wiki-markup
3. \[#Q3 Why do I get java.lang.NoClassDefFoundError: org/xml/sax/InputSource?\] \\
   

Answers

 jsp:useBean 

...

• Your bean is packaged in a class.
• You have fully qualified your class name (eg:

  No Format
  com.bar.package.MyClass

  ) OR
• You have imported your class into your jsp (eg:

  No Format
  <%@ pageimport="com.bar.package.MyClass"%>

  )
  

 java.lang.NoClassDefFoundError: javax/servlet/Filter

...

You probably have servlet.jar floating around somewhere it shouldn't be. This really messes up the classloaders since Tomcat's classloaders don't act quite as normal as one expects (see links above). servlet.jar should only be found only once in $CATALINA_HOME/common/lib.

 java.lang.NoClassDefFoundError: org/xml/sax/InputSource 

...