Java Servlet on Tomcat Server (File Not Found Error)

Question

I'm having a problem running java servlets on my Tomcat server (V7.0.72). The problem is the Tomcat Server serves files already existing but when I create a new webapp it says "File Not Found".

For working examples/HelloWorld:

For not working servlets/HelloWorld:

The Directory Structure is :

 tomcat
  |    
  +-- webapps
       |
       +- servlets
           |
           +- WEB-INF
               |
               +- classes
               |   |
               |   +- HelloWorld.class
               |   | 
               |   +- HelloWorld.java
               |    
               +- web.xml

Contents of web.xml:

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                          http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0"
         metadata-complete="true">

    <description>
        Servlet and JSP Examples.
    </description>
    <display-name>Servlet and JSP Examples</display-name>

    <!-- Define example filters -->
    <filter>
        <filter-name>Timing filter</filter-name>
        <filter-class>filters.ExampleFilter</filter-class>
        <init-param>
            <param-name>attribute</param-name>
            <param-value>filters.ExampleFilter</param-value>
        </init-param>
    </filter>

    <filter>
        <filter-name>Request Dumper Filter</filter-name>
        <filter-class>org.apache.catalina.filters.RequestDumperFilter</filter-class>
    </filter>

    <!-- Example filter to set character encoding on each request -->
    <filter>
        <filter-name>Set Character Encoding</filter-name>
        <filter-class>org.apache.catalina.filters.SetCharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>EUC_JP</param-value>
        </init-param>
        <init-param>
            <param-name>ignore</param-name>
            <param-value>true</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>128</param-value>
        </init-param>
        <init-param>
            <param-name>compressionBuffer</param-name>
            <param-value>8192</param-value>
        </init-param>
        <init-param>
            <param-name>compressionMimeTypes</param-name>
            <param-value>text/html,text/plain,text/xml</param-value>
        </init-param>
        <init-param>
            <param-name>debug</param-name>
            <param-value>0</param-value>
        </init-param>
    </filter>

    <!-- Define filter mappings for the timing filters -->
    <!--
    <filter-mapping>
        <filter-name>Timing Filter</filter-name>
        <url-pattern>/*</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>ServletToJsp</servlet-name>
        <servlet-class>ServletToJsp</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>ChatServlet</servlet-name>
        <servlet-class>chat.ChatServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>CompressionFilterTestServlet</servlet-name>
        <servlet-class>compressionFilters.CompressionFilterTestServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>HelloWorld</servlet-name>
        <servlet-class>HelloWorld</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>ChatServlet</servlet-name>
        <url-pattern>/servlets/chat/chat</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>CompressionFilterTestServlet</servlet-name>
        <url-pattern>/CompressionTest</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>HelloWorld</servlet-name>
        <url-pattern>/HelloWorld</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>RequestInfoExample</servlet-name>
        <url-pattern>/servlets/servlet/RequestInfoExample/*</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>RequestHeaderExample</servlet-name>
        <url-pattern>/servlets/servlet/RequestHeaderExample</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>RequestParamExample</servlet-name>
        <url-pattern>/servlets/servlet/RequestParamExample</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>CookieExample</servlet-name>
        <url-pattern>/servlets/servlet/CookieExample</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>SessionExample</servlet-name>
        <url-pattern>/servlets/servlet/SessionExample</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>ServletToJsp</servlet-name>
        <url-pattern>/servletToJsp</url-pattern>
    </servlet-mapping>

    <jsp-config>
        <taglib>
            <taglib-uri>
                http://tomcat.apache.org/debug-taglib
            </taglib-uri>
            <taglib-location>
                /WEB-INF/jsp/debug-taglib.tld
            </taglib-location>
        </taglib>

        <taglib>
            <taglib-uri>
                http://tomcat.apache.org/example-taglib
            </taglib-uri>
            <taglib-location>
                /WEB-INF/jsp/example-taglib.tld
            </taglib-location>
        </taglib>

        <taglib>
            <taglib-uri>
                http://tomcat.apache.org/jsp2-example-taglib
            </taglib-uri>
            <taglib-location>
                /WEB-INF/jsp2/jsp2-example-taglib.tld
            </taglib-location>
        </taglib>

        <jsp-property-group>
            <description>
                Special property group for JSP Configuration JSP example.
            </description>
            <display-name>JSPConfiguration</display-name>
            <url-pattern>/jsp/jsp2/misc/config.jsp</url-pattern>
            <el-ignored>true</el-ignored>
            <page-encoding>ISO-8859-1</page-encoding>
            <scripting-invalid>true</scripting-invalid>
            <include-prelude>/jsp/jsp2/misc/prelude.jspf</include-prelude>
            <include-coda>/jsp/jsp2/misc/coda.jspf</include-coda>
        </jsp-property-group>
    </jsp-config>

    <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-type>java.lang.Integer</env-entry-type>
      <env-entry-value>15</env-entry-value>
    </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>

    <!-- Async examples -->
    <servlet>
        <servlet-name>async0</servlet-name>
        <servlet-class>async.Async0</servlet-class>
        <async-supported>true</async-supported>
    </servlet>
    <servlet-mapping>
        <servlet-name>async0</servlet-name>
        <url-pattern>/async/async0</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>async1</servlet-name>
        <servlet-class>async.Async1</servlet-class>
        <async-supported>true</async-supported>
    </servlet>
    <servlet-mapping>
        <servlet-name>async1</servlet-name>
        <url-pattern>/async/async1</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>async2</servlet-name>
        <servlet-class>async.Async2</servlet-class>
        <async-supported>true</async-supported>
    </servlet>
    <servlet-mapping>
        <servlet-name>async2</servlet-name>
        <url-pattern>/async/async2</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>async3</servlet-name>
        <servlet-class>async.Async3</servlet-class>
        <async-supported>true</async-supported>
    </servlet>
    <servlet-mapping>
        <servlet-name>async3</servlet-name>
        <url-pattern>/async/async3</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>stock</servlet-name>
        <servlet-class>async.AsyncStockServlet</servlet-class>
        <async-supported>true</async-supported>
    </servlet>
    <servlet-mapping>
        <servlet-name>stock</servlet-name>
        <url-pattern>/async/stockticker</url-pattern>
    </servlet-mapping>

    <!-- WebSocket Examples using Deprecated Tomcat 7 API-->
    <servlet>
        <servlet-name>wsEchoStream</servlet-name>
        <servlet-class>websocket.tc7.echo.EchoStream</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>wsEchoStream</servlet-name>
        <url-pattern>/websocket/tc7/echoStream</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>wsEchoMessage</servlet-name>
        <servlet-class>websocket.tc7.echo.EchoMessage</servlet-class>
        <!-- Uncomment the following block to increase the default maximum
             WebSocket buffer size from 2MB to 20MB which is required for the
             Autobahn test suite to pass fully. -->
        <!--
        <init-param>
          <param-name>byteBufferMaxSize</param-name>
          <param-value>20971520</param-value>
        </init-param>
        <init-param>
          <param-name>charBufferMaxSize</param-name>
          <param-value>20971520</param-value>
        </init-param>
        -->
    </servlet>
    <servlet-mapping>
        <servlet-name>wsEchoMessage</servlet-name>
        <url-pattern>/websocket/tc7/echoMessage</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>wsChat</servlet-name>
        <servlet-class>websocket.tc7.chat.ChatWebSocketServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>wsChat</servlet-name>
        <url-pattern>/websocket/tc7/chat</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>wsSnake</servlet-name>
        <servlet-class>websocket.tc7.snake.SnakeWebSocketServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>wsSnake</servlet-name>
        <url-pattern>/websocket/tc7/snake</url-pattern>
    </servlet-mapping>
    <!-- Websocket examples -->
    <listener>
        <listener-class>websocket.drawboard.DrawboardContextListener</listener-class>
    </listener>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.xhtml</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

</web-app>

Contents of HelloWorld.java:

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ResourceBundle;

public class HelloWorld extends HttpServlet {

    private static final long serialVersionUID = 1L;

    @Override
    public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
            throws IOException, ServletException {
        ResourceBundle rb =
                ResourceBundle.getBundle("LocalStrings", request.getLocale());
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        out.println("<html>");
        out.println("<head>");

        String title = rb.getString("helloworld.title");

        out.println("<title>" + title + "</title>");
        out.println("</head>");
        out.println("<body bgcolor=\"white\">");

        // note that all links are created to be relative. this
        // ensures that we can move the web application that this
        // servlet belongs to to a different place in the url
        // tree and not have any harmful side effects.

        // XXX
        // making these absolute till we work out the
        // addition of a PathInfo issue

        out.println("<a href=\"../helloworld.html\">");
        out.println("<img src=\"../images/code.gif\" height=24 " +
                "width=24 align=right border=0 alt=\"view code\"></a>");
        out.println("<a href=\"../index.html\">");
        out.println("<img src=\"../images/return.gif\" height=24 " +
                "width=24 align=right border=0 alt=\"return\"></a>");
        out.println("<h1>" + title + "</h1>");
        out.println("</body>");
        out.println("</html>");
    }
}

Any Suggestions are welcome. Thank you.

Answer 1

I'm not sure where you got that web.xml but I would encourage you to start small - it's hard to understand what is what in there. Make your life easy and start with something like:

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                          http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0"
         metadata-complete="true">

    <servlet>
        <servlet-name>hello</servlet-name>
        <servlet-class>HelloWorld</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>hello</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
</web-app>

As you need it you can add filters and the like.

As an aside, you don't even need web.xml anymore if you don't want it. You could change your servlet to start with something like:

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(urlPatterns = {"/hello"})
public class HelloWorld extends HttpServlet {

instead. This maps the servlet to /hello in your web application, the same as the web.xml does.