"The requested resource (/hello) is not available" Error of Servlet

Question

Hello all,
I get HTTP STATUS 404 Error which states "The requested resource (/hello) is not available" even thought according to me I am doing everything perfectly.
Here is more information. If you can find out where the proble might be please
let me know because I am working on this for more than 9 hours.
I AM USING-<br>
TOMCAT 5.5.26 <br>
JRE 6 <br>
J2SDK 1.4.0 <br>
</B>
<BR><BR>
SYSTEM VARIABLES :<br>
<B>
CLASSPATH
</B>
C:\apache-tomcat-5.5.26\common\lib\servlet-api.jar <BR>
<B> JAVA_HOME</B> D:\j2sdk1.4.0
<BR>
<B>JRE_HOME</B> C:\Program Files\Java\jre6
<BR>
<B>TOMCAT_HOME </B>C:\apache-tomcat-5.5.26
<BR>
<P>
I have placed my hello.class file inside
<b>C:\apache-tomcat-5.5.26\webapps\ROOT\WEB-INF\classes</b>
also, i have modified web.xml file as<br>
<b>
<servlet>
<servlet-name>hello</servlet-name>
<servlet-class>hello</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>hello</url-pattern>
</servlet-mapping>
</b><br><br>
But still I am not able to access my servlet when i type
http://localhost:8080/hello
I get the error I mentioned above.

Answer 1

Hi..Thanks for all those who have replied earlier. I feel I should add some more information.
I dont know what PACKAGE NAME you are talking about
I am pasting contents of my XML file located in :
**apache-tomcat-5.5.26\webapps\ROOT\WEB-INF\web.xml**
-->
- <web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4">
<display-name>Welcome to Tomcat</display-name>
<description>Welcome to Tomcat</description>
- <!-- JSPC servlet mappings start
-->
- <servlet>
<servlet-name>org.apache.jsp.index_jsp</servlet-name>
<servlet-class>org.apache.jsp.index_jsp</servlet-class>
</servlet>
- <servlet-mapping>
<servlet-name>org.apache.jsp.index_jsp</servlet-name>
<url-pattern>/index.jsp</url-pattern>
</servlet-mapping>
- <!-- JSPC servlet mappings end
-->
</web-app>
web.xml file located in
apache-tomcat-5.5.26\webapps\servlets-examples\WEB-INF
is given below:
<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version
2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<display-name>Servlet 2.4 Examples</display-name>
<description>
Servlet 2.4 Examples.
</description>
<!-- Define servlet-mapped and path-mapped example filters -->
<filter>
<filter-name>Servlet Mapped Filter</filter-name>
<filter-class>filters.ExampleFilter</filter-class>
     <init-param>
     <param-name>attribute</param-name>
<param-value>filters.ExampleFilter.SERVLET_MAPPED</param-value>
     </init-param>
</filter>
<filter>
<filter-name>Path Mapped Filter</filter-name>
<filter-class>filters.ExampleFilter</filter-class>
     <init-param>
     <param-name>attribute</param-name>
<param-value>filters.ExampleFilter.PATH_MAPPED</param-value>
     </init-param>
</filter>
<filter>
<filter-name>Request Dumper Filter</filter-name>
<filter-class>filters.RequestDumperFilter</filter-class>
</filter>
<!-- Example filter to set character encoding on each request -->
<filter>
<filter-name>Set Character Encoding</filter-name>
<filter-class>filters.SetCharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>EUC_JP</param-value>
</init-param>
</filter>
<filter>
<filter-name>Compression Filter</filter-name>
<filter-class>compressionFilters.CompressionFilter</filter-class>
<init-param>
<param-name>compressionThreshold</param-name>
<param-value>10</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>0</param-value>
</init-param>
</filter>
<!-- Define filter mappings for the defined filters -->
<filter-mapping>
<filter-name>Servlet Mapped Filter</filter-name>
     <servlet-name>invoker</servlet-name>
</filter-mapping>
<filter-mapping>
<filter-name>Path Mapped Filter</filter-name>
     <url-pattern>/servlet/*</url-pattern>
</filter-mapping>
<!-- Example filter mapping to apply the "Set Character Encoding"
filter
to all requests processed by this web application -->
<!--
<filter-mapping>
<filter-name>Set Character Encoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
-->
<!--
<filter-mapping>
<filter-name>Compression Filter</filter-name>
<url-pattern>/CompressionTest</url-pattern>
</filter-mapping>
-->
<!--
<filter-mapping>
<filter-name>Request Dumper Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
-->
<!-- Define example application events listeners -->
<listener>
<listener-class>listeners.ContextListener</listener-class>
</listener>
<listener>
<listener-class>listeners.SessionListener</listener-class>
</listener>
<!-- Define servlets that are included in the example application
-->
<servlet>
<servlet-name>CompressionFilterTestServlet</servlet-name>
<servlet-class>compressionFilters.CompressionFilterTestServlet</servlet
-class>
</servlet>
<servlet>
<servlet-name>hello</servlet-name>
<servlet-class>hello</servlet-class>
</servlet>
</servlet>
<servlet>
<servlet-name>HelloWorldExample</servlet-name>
<servlet-class>HelloWorldExample</servlet-class>
</servlet>
<servlet>
<servlet-name>RequestInfoExample</servlet-name>
<servlet-class>RequestInfoExample</servlet-class>
</servlet>
<servlet>
<servlet-name>RequestHeaderExample</servlet-name>
<servlet-class>RequestHeaderExample</servlet-class>
</servlet>
<servlet>
<servlet-name>RequestParamExample</servlet-name>
<servlet-class>RequestParamExample</servlet-class>
</servlet>
<servlet>
<servlet-name>CookieExample</servlet-name>
<servlet-class>CookieExample</servlet-class>
</servlet>
<servlet>
<servlet-name>SessionExample</servlet-name>
<servlet-class>SessionExample</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CompressionFilterTestServlet</servlet-name>
<url-pattern>/CompressionTest</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>HelloWorldExample</servlet-name>
<url-pattern>/servlet/HelloWorldExample</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>RequestInfoExample</servlet-name>
<url-pattern>/servlet/RequestInfoExample/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>RequestHeaderExample</servlet-name>
<url-pattern>/servlet/RequestHeaderExample</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>RequestParamExample</servlet-name>
<url-pattern>/servlet/RequestParamExample</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>CookieExample</servlet-name>
<url-pattern>/servlet/CookieExample</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>SessionExample</servlet-name>
<url-pattern>/servlet/SessionExample</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>/servlet/hello</url-pattern>
</servlet-mapping>
<security-constraint>
<display-name>Example Security Constraint</display-name>
<web-resource-collection>
<web-resource-name>Protected Area</web-resource-name>
     <!-- Define the context-relative URL(s) to be protected -->
<url-pattern>/jsp/security/protected/*</url-pattern>
     <!-- If you list http methods, only those methods are
protected -->
     <http-method>DELETE</http-method>
<http-method>GET</http-method>
<http-method>POST</http-method>
     <http-method>PUT</http-method>
</web-resource-collection>
<auth-constraint>
<!-- Anyone with one of the listed roles may access this area
-->
<role-name>tomcat</role-name>
     <role-name>role1</role-name>
</auth-constraint>
</security-constraint>
<!-- Default login configuration uses form-based authentication -->
<login-config>
<auth-method>FORM</auth-method>
<realm-name>Example Form-Based Authentication Area</realm-name>
<form-login-config>
<form-login-page>/jsp/security/protected/login.jsp</form-login-page>
<form-error-page>/jsp/security/protected/error.jsp</form-error-page>
</form-login-config>
</login-config>
<!-- Security roles referenced by this web application -->
<security-role>
<role-name>role1</role-name>
</security-role>
<security-role>
<role-name>tomcat</role-name>
</security-role>
<!-- Environment entry examples -->
<!--env-entry>
<env-entry-description>
The maximum number of tax exemptions allowed to be set.
</env-entry-description>
<env-entry-name>maxExemptions</env-entry-name>
<env-entry-value>15</env-entry-value>
<env-entry-type>java.lang.Integer</env-entry-type>
</env-entry-->
<env-entry>
<env-entry-name>minExemptions</env-entry-name>
<env-entry-type>java.lang.Integer</env-entry-type>
<env-entry-value>1</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>foo/name1</env-entry-name>
<env-entry-type>java.lang.String</env-entry-type>
<env-entry-value>value1</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>foo/bar/name2</env-entry-name>
<env-entry-type>java.lang.Boolean</env-entry-type>
<env-entry-value>true</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>name3</env-entry-name>
<env-entry-type>java.lang.Integer</env-entry-type>
<env-entry-value>1</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>foo/name4</env-entry-name>
<env-entry-type>java.lang.Integer</env-entry-type>
<env-entry-value>10</env-entry-value>
</env-entry>
</web-app>
My program hello.java is given below
import java.io.*;
import javax.servlet.http.*;
import javax.servlet.*;
public class hello extends HttpServlet {
public void doGet (HttpServletRequest req,
HttpServletResponse res)
throws ServletException, IOException
PrintWriter out = res.getWriter();
out.println("Hello, world!");
out.close();
}