Compile problem using TOMCAT 5.0 and Apache ANT

Question

I got some sample from book.
i just follow the step, place it the class file. it work. it run. show all the detail.
but when i wan to compile it from java file, error came out
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: Error allocating a servlet instance
     org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
     org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
     org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
     org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
     org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
     org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
     java.lang.Thread.run(Unknown Source)
root cause
java.lang.NoClassDefFoundError: com/jspbook/HelloWorld (wrong name: HelloWorld)
     java.lang.ClassLoader.defineClass1(Native Method)
     java.lang.ClassLoader.defineClass(Unknown Source)
     java.security.SecureClassLoader.defineClass(Unknown Source)
     org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1634)
     org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:860)
     org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1307)
     org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1189)
     org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
     org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
     org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
     org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
     org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
     org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
     java.lang.Thread.run(Unknown Source)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.in CMD:
set java_home = C:\Program Files\Java\jdk1.5.0_08
set classpath = C:\Program Files\Apache Software Foundation\Tomcat 5.0\common\lib
and Apache tomcat originally dont have servlet.jar but servlet-api.jar, i copy the servlet.jar from my friend
i compile it using Apache ANT
here the build.xml
<?xml version="1.0" ?>
<project name="jspbook" default="build" basedir=".">
  <target name="build">
    <echo>Starting Build </echo>
    <!-- Turn Tomcat Off -->
    <antcall target="tomcatOff"/>
    <!-- Compile Everything -->
    <antcall target="compile"/>
    <!-- Turn Tomcat On -->
    <antcall target="tomcatOn"/>
    <echo>Build Finished </echo>
  </target>
  <target name="tomcatOff">
    <echo>Turning Off Tomcat </echo>
    <exec executable="bash" os="Windows">
      <arg value="../../bin/shutdown.bat"/>
    </exec>
    <exec executable="bash" os="Linux">
      <arg value="../../bin/shutdown.sh"/>
    </exec>
  </target>
  <target name="tomcatOn">
    <echo>Starting Tomcat </echo>
    <exec executable="bash" os="Windows">
      <arg value="../../bin/startup.bat"/>
    </exec>
    <exec executable="bash" os="Linux">
      <arg value="../../bin/startup.sh"/>
    </exec>
  </target>
  <target name="compile">
    <javac
      srcdir="WEB-INF/classes"
      extdirs="WEB-INF/lib:../../common/lib"
      classpath="../../common/lib/servlet.jar"
      deprecation="yes"
      verbose="no">
      <include name="com/jspbook/**"/>
    </javac>
  </target>
</project>compile success, but error in IE
paste the sample class file in,restart tomcat. i work again!
what is the problem!
even i compile the code inside the Jcreator, after set required libraries to servlet.jar or servlet-api.jar
compile it, success then run it in IE, same error!!!.
what should i do.
stil a beginer in servlet and jsp anyway.

Answer 1

and Apache tomcat originally dont have servlet.jar but servlet-api.jar, i copy the servlet.jar from my friend servlet.jar is an OLD version, you should only use servlet-api.jar!
wrong name: HelloWorldPerhaps there is a mistake in the class or packagename of the source file. Post the source here.