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Permalink to this page: https://cwiki.apache.org/confluence/x/tSklBg
Preface
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:
Classloader HOWTO pages: \[http://tomcat.apache.org/tomcat-4.1-doc/class-loader-howto.html Tomcat 4.1\], \[http://tomcat.apache.org/tomcat-5.0-doc/class-loader-howto.html Tomcat 5.0\], \[http://tomcat.apache.org/tomcat-5.5-doc/class-loader-howto.html Tomcat 5.5\].Wiki Markup Wiki Markup \[http://marc.theaimsgroup.com/?t=104317529200004&r=1&w=2 Don't\] \[http://marc.theaimsgroup.com/?t=104380440100003&r=1&w=2 use\] \[http://marc.theaimsgroup.com/?t=96947656900002&r=1&w=2 packageless\] \[http://marc.theaimsgroup.com/?t=104491020100002&r=1&w=2 classes\] \[http://marc.theaimsgroup.com/?t=104265576200003&r=1&w=2 and\] \[http://marc.theaimsgroup.com/?t=104249748300001&r=1&w=2 declare\] \[http://marc.theaimsgroup.com/?t=102996950100003&r=1&w=2 all\] \[http://marc.theaimsgroup.com/?t=102922189400001&r=1&w=2 imported classes\]!
- Tomcat 9.0, Tomcat 8.5, Tomcat 7.0, (historic: Tomcat 6.0).
- Don't use packageless classes and declare all imported classes!
- Another answer to a classloader issue
\[http://marc.theaimsgroup.com/?l=tomcat-user&m=103843452413727&w=2 Another answer to a classloader issue\] \\Wiki Markup
If you get a NoClassDefFoundError
exception, the root cause might be the same as for a ClassNotFound
exception.
Questions
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- not working?
- Why do I get java.lang.NoClassDefFoundError: javax/servlet/Filter?
- Why do I get java.lang.NoClassDefFoundError: org/xml/sax/InputSource?
Answers
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jsp:useBean
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is not working?
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Make sure:
- Your bean is packaged in a class.
You have fully qualified your class name (
eg:No Format e.g.:
com.bar.package.MyClass
) OR
You have imported your class into your jsp (
eg: <%@ pageimportNo Format e.g.:
)<%@ page import="com.bar.package.MyClass"%>
)
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java.lang.NoClassDefFoundError:
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javax/servlet/Filter
?
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You probably have servlet-api.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-api.jar should only be found only once in $CATALINA_HOME/common/lib.
Anchor | ||||
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java.lang.NoClassDefFoundError:
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org/xml/sax/InputSource
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?
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You have conflicting XML api jar files in your classpath. Read the README or RELEASE-NOTES for more information.
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