Hello guys,

I try to run a simple example of JSP tag library. but I am getting the
following Exception .
I am not able to understand what this is all about.

Here is Exception message:

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented
it from fulfilling this request.

exception

org.apache.jasper.JasperException: Failed to load or instantiate
TagExtraInfo class: tw.com.javaworld.CH15.TEI
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:375)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

org.apache.jasper.JasperException: Failed to load or instantiate
TagExtraInfo class: tw.com.javaworld.CH15.TEI
    org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:50)
    org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407)
    org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:279)
    org.apache.jasper.compiler.TagLibraryInfoImpl.createTagInfo(TagLibraryInfoImpl.java:422)
    org.apache.jasper.compiler.TagLibraryInfoImpl.parseTLD(TagLibraryInfoImpl.java:248)
    org.apache.jasper.compiler.TagLibraryInfoImpl.<init>(TagLibraryInfoImpl.java:162)
    org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:423)
    org.apache.jasper.compiler.Parser.parseDirective(Parser.java:492)
    org.apache.jasper.compiler.Parser.parseElements(Parser.java:1552)
    org.apache.jasper.compiler.Parser.parse(Parser.java:126)
    org.apache.jasper.compiler.ParserController.doParse(ParserController.java:211)
    org.apache.jasper.compiler.ParserController.parse(ParserController.java:100)
    org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:155)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:295)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:276)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:264)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:563)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:303)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.ClassCastException: tw.com.javaworld.CH15.TEI cannot be cast
to javax.servlet.jsp.tagext.TagExtraInfo
    org.apache.jasper.compiler.TagLibraryInfoImpl.createTagInfo(TagLibraryInfoImpl.java:420)
    org.apache.jasper.compiler.TagLibraryInfoImpl.parseTLD(TagLibraryInfoImpl.java:248)
    org.apache.jasper.compiler.TagLibraryInfoImpl.<init>(TagLibraryInfoImpl.java:162)
    org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:423)
    org.apache.jasper.compiler.Parser.parseDirective(Parser.java:492)
    org.apache.jasper.compiler.Parser.parseElements(Parser.java:1552)
    org.apache.jasper.compiler.Parser.parse(Parser.java:126)
    org.apache.jasper.compiler.ParserController.doParse(ParserController.java:211)
    org.apache.jasper.compiler.ParserController.parse(ParserController.java:100)
    org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:155)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:295)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:276)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:264)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:563)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:303)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

note The full stack trace of the root cause is available in the Apache
Tomcat/5.5.17 logs.
Apache Tomcat/5.5.17

Here is my  part of MyTaglib.tld file:

<tag>
     <description>Simplest example:Hello</description>
     <name>Hello</name>
     <tag-class>tw.com.javaworld.CH15.Hello</tag-class>
     <body-content>empty</body-content>
   </tag>

   <tag>
     <description>Hello TEI</description>
     <name>Hello_TEI</name>
     <tag-class>tw.com.javaworld.CH15.Hello_TEI</tag-class>
     <tei-class>tw.com.javaworld.CH15.TEI</tei-class>
     <body-content>empty</body-content>

Everything seems correct. what's wrong. Any hint is appreciated. thanks
a lot!