I'm not able to get FrontMan working

[Hussein Baghdadi]

Hi.
I'm trying to use Mr. Bear's FrontMan and I got this exception:

javax.servlet.ServletException
        at weblogic.servlet.internal.ServletStubImpl.createServlet(ServletStubImpl.java:919)
        at weblogic.servlet.internal.ServletStubImpl.createInstances(ServletStubImpl.java:883)
        at weblogic.servlet.internal.ServletStubImpl.prepareServlet(ServletStubImpl.java:822)
        at weblogic.servlet.internal.WebAppServletContext.preloadServlet(WebAppServletContext.java:3333)
        at weblogic.servlet.internal.WebAppServletContext.preloadServlets(WebAppServletContext.java:3278)
        at weblogic.servlet.internal.WebAppServletContext.preloadResources(WebAppServletContext.java:3259)
        at weblogic.servlet.internal.WebAppServletContext.setStarted(WebAppServletContext.java:5949)
        at weblogic.servlet.internal.WebAppModule.start(WebAppModule.java:862)
        at weblogic.j2ee.J2EEApplicationContainer.start(J2EEApplicationContainer.java:2127)
        at weblogic.j2ee.J2EEApplicationContainer.activate(J2EEApplicationContainer.java:2168)
        at weblogic.j2ee.J2EEApplicationContainer.activate(J2EEApplicationContainer.java:2115)
        at weblogic.management.deploy.slave.SlaveDeployer$Application.setActivation(SlaveDeployer.java:3082)
        at weblogic.management.deploy.slave.SlaveDeployer.setActivationStateForAllApplications(SlaveDeployer.java:1751)
        at weblogic.management.deploy.slave.SlaveDeployer.resume(SlaveDeployer.java:359)
        at weblogic.management.deploy.DeploymentManagerServerLifeCycleImpl.resume(DeploymentManagerServerLifeCycleImpl.j
ava:229)
        at weblogic.t3.srvr.SubsystemManager.resume(SubsystemManager.java:131)
        at weblogic.t3.srvr.T3Srvr.resume(T3Srvr.java:966)
        at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:361)
        at weblogic.Server.main(Server.java:32)
Caused by: java.lang.ExceptionInInitializerError
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
        at java.lang.Class.newInstance0(Class.java:308)
        at java.lang.Class.newInstance(Class.java:261)
        at weblogic.servlet.internal.ServletStubImpl$ServletInitAction.run(ServletStubImpl.java:1026)
        at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
        at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121)
        at weblogic.servlet.internal.ServletStubImpl.createServlet(ServletStubImpl.java:904)
        ... 18 more
Caused by: java.lang.NullPointerException
        at java.util.Hashtable.get(Hashtable.java:333)
        at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:270)
        at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:414)
        at org.bibeault.frontman.CommandBroker.<clinit>(CommandBroker.java:66)
        ... 28 more

Any ideas?

[Ben Souther]

Maybe you could tell us a little about how you set things up.
Which application server, OS, how you configured it.
Maybe post some of your code.

[Hussein Baghdadi]

I have FrontMan.jar, commons-logging.jar in my WEB-INF/lib
Snippet of web.xml:

<servlet>
 
  <servlet-name>CommandBroker</servlet-name>
 
  <servlet-class>org.bibeault.frontman.CommandBroker</servlet-class>
 
  <init-param>
 
    <param-name>commandVerbsResourcePath</param-name>
 
    <param-value>/WEB-INF/command.verbs.properties</param-value>
 
  </init-param>
 
  <init-param>
 
    <param-name>viewNamesResourcePath</param-name>
 
    <param-value>/WEB-INF/view.names.properties</param-value>
 
  </init-param>
 
  <load-on-startup>1</load-on-startup>
 
</servlet>
 

Two files are created under WEB-INF directly:
view.names.properties
command.verbs.properties
I'm using WebLogic8.1 on Windows 2K
My first command:

public class GetGroupItemsCommand
    implements Command {
 
  public void execute(CommandContext commandContext) throws IOException, ServletException {
    HttpServletRequest request = commandContext.getRequest();
    String group = request.getParameter("group");
    if (group == null || "".equals(group.trim())) {
      request.setAttribute("missingGroup", "You have to choose an item group");
      commandContext.forwardToView("Groups");
      return;
    }
    HashSet groupItems = (HashSet) ItemUtility.getItemTypes(group);
    request.setAttribute("groupItems", groupItems);
    commandContext.forward("GroupItems");
  }
 
}

[Ben Souther]

at java.util.Hashtable.get(Hashtable.java:333)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:270)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:414)
at org.bibeault.frontman.CommandBroker.<clinit>(CommandBroker.java:66)
... 28 more

Can you find the log that contains the full stack trace.
Somewhere in the '28 more' there should be a line that points to one of your classes.

[Bear Bibeault]

What's at CommandBroker.java line 66? I'm away from my source at the moment and can't peek myself!

It looks from the stack trace like it's getting an NPE while trying to create the logger and that just seems weird.

[Bear Bibeault]

OK, answered my own question. Line 66 is:

    
    public class CommandBroker extends HttpServlet {
-->    private static Log log = LogFactory.getLog( CommandBroker.class.getName() ); 

The line itself isn't NPE-ing, but rather a few levels into the call to getLog(). This is not anything I've ever seen before.

How do you have logging set up? Using Log4J or letting commons logging default to using java.util.logging?
[ November 22, 2007: Message edited by: Bear Bibeault ]

[Hussein Baghdadi]

I let the commons logging uses java.util.logging

[Bear Bibeault]

Wow, that's really weird. Not using Weblogic, I'm not sure how to further diagnose the logging issue. Have you used commons logging in other apps successfully?

It's obvious not a FrontMan issue as it works fine in other app servers and there's nothing it could possibly be doing on this line of code to cause an NPE deeper into the logging.

Is there a Jakarta mailing list for commons logging? What about Weblogic forums? Any mention of commons logging issues?