Problem deploying servlets in JBoss 5.1 on eclipse.
- by Jeremy Goodell
Yesterday I created a simple image servlet and attempted to deploy it. I am getting an error on JBoss startup, and then further errors on trying to invoke the servlet.
I spent about 8 hours yesterday searching the web for answers and trying different scenarios. I ended up making my JBoss problems worse and then fixing them, but I never did get the servlet to work.
The servlet is com.controller.MyImageServlet, and looks like this:
package com.controller;
import javax.servlet.http.*;
/**
* Servlet implementation class MyImageServlet
*/
public class MyImageServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public MyImageServlet() {
super();
}
// Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
/* ... */
}
}
The tags I've added to web.xml looks like this:
<servlet>
<servlet-name>ImageServlet</servlet-name>
<servlet-class>com.controller.MyImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageServlet</servlet-name>
<url-pattern>/CERTIMAGE/*</url-pattern>
</servlet-mapping>
On server startup, this is the only indication in the log that something is amiss:
01:59:25,328 WARN [JAXWSDeployerHookPreJSE] Cannot load servlet class: com.controller.MyImageServlet
When I try the URL pattern (http://localhost:9980/CERTIMAGE/1), I get the following stack trace in the log (and in the Browser):
01:59:39,640 INFO [[/]] Marking servlet ImageServlet as unavailable
01:59:39,640 ERROR [[ImageServlet]] Allocate exception for servlet ImageServlet
java.lang.ClassNotFoundException: com.controller.MyImageServlet
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
at org.jboss.web.tomcat.service.TomcatInjectionContainer.newInstance(TomcatInjectionContainer.java:262)
at org.jboss.web.tomcat.service.TomcatInjectionContainer.newInstance(TomcatInjectionContainer.java:256)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1006)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:777)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:129)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
If I try the URL pattern again, I get the following message in the log:
09:33:32,390 INFO [[ImageServlet]] Servlet ImageServlet is currently unavailable
I have verified that MyImageServlet.class is in the WAR at WEB-INF/classes/com/controller/images. As a matter of fact, I even added some code to one of my JSPs to attempt to instantiate the Servlet and call the doGet method. This actually works and outputs the correct debug sequences to the log indicating that the Servlet constructor and doGet methods were called.
I also tried following some instructions for creating/deploying a very simple HelloWorld servlet, and that has exactly the same problem. Note that web.xml already contained a servlet put there by JBoss: org.jboss.web.tomcat.service.StatusServlet -- that Servlet does not give any errors in the log. As an experiment, I removed ".web" from that path and ended up getting exactly the same error as I'm getting on my Servlet. So it would appear that JBoss is not able to locate my Servlet given the specified path. Just for kicks, I've tried all sorts of other paths, like just plain MyImageServlet, controller.MyImageServlet, and more. Also, the servlet was originally named ImageServlet, but I attempted the name change thinking maybe there was some conflict with an existing ImageServlet. In all cases, the behavior is the same.
After all of my research yesterday, I would say that this appears to be a problem with the JBoss servlet container, and I also learned that JBoss 5.1.0.GA should come bundled with a tomcat servlet container. I installed JBoss on my PC (Windows XP) myself less than 2 months ago (from jboss.org) and used it pretty much as is. Note that I am running on JDK 1.6, so I did use the jboss-jdk6 installation version. I am running on Windows, but I also deploy to a Linux virtual dedicated server. I deployed the current version of my program, including the servlet to the Linux box, but I get the exact same errors. I'm reluctant to just try reinstalling JBoss, since it's hard to place the blame on the JBoss installation when I get the same errors on two completely different installations.
I am a bit suspicious of the bundled tomcat servlet container, because using eclipse, I haven't been able to locate any indication that there is a tomcat bundled into JBoss. I did locate servlet-api.jar in the JBoss common/lib directory. This is on the eclipse build path.
One possibly useful note: I had previously used a standalone tomcat server for other projects using the same eclipse, so maybe it's some sort of eclipse issue? But, as I said, I do get the same errors when I deploy to the Linux server, and that deployment process just involves ftping files to the server and then putting them into the deployed war package and restarting JBoss.
Thanks for any help you can provide.
