No ClassLoaders found

[bwinspur]

Hi, I am trying to initialize the servlet context by dynamically instantiating
a servlet-specific object, but am having problems with dynamically
loading class com.wynnon.commandTunnel.LoopbackAdaptor, which resides in
WEB-INF/classes/. Initially I used the statement:

srvrClass = Class.forName(fqn);

which threw

java.lang.ClassNotFoundException: No ClassLoaders found for: com.wynnon.commandTunnel.LoopbackAdaptor

Then, after reading through the JBoss JMX Implementation Architecture
chapter of the 3.2.3 book, I tried to load the class using the servlet's
classloader, i.e.

srvrClass = this.getClass().getClassLoader().loadClass(fqn);

assuming that I would be supplying the missing classloader, perhaps WARLoader.
However, I got exactly the same exception: ... No Classloaders Found...

Questions
---------
1. What does the exception mean?

2. Is there a way to associate a class loader with a class that
does not have one, before one attempts to load the class ?

3. Is this a jboss or a tomcat issue ?

4. Can anyone direct me to an example of dynamic instantiation
in the jboss/tomcat servlet environment?

Thanks for your attention,

Bill.

[juha]

What version of JBoss are you running? What does your jboss-web.sar/META-INF/jboss-service.xml settings look like? Did you try the thread context classloader?

[bwinspur]

juha, thanks for the reply,

1. I'm running jboss 3.2.3

2. I'm assuming that jboss-web.sar/META-INF/jboss-service.xml
you ask about, corresponds to
jboss-3.2.3/server/default/deploy/jbossweb-tomcat41.sar, in
which case its META-INF/jboss-service.xml looks like below.

3. I just tried using the thread context classloader, and it
worked! My class loaded and instantiated.

Thanks a bunch, I'm new to jboss and the level of response is
as impressive as the implementation. I'll study the jvm spec
etc. to get a better understanding of defining and initiating
class loaders, quite new to me. Thanks again.

Bill.
=============================================================

<?xml version="1.0" encoding="UTF-8" ?>
- <!-- The service configuration for the embedded Tomcat4.1.x web container

-->
-
-
- <!--
Get the flag indicating if the normal Java2 parent first class
loading model should be used over the servlet 2.3 web container first
model.


-->
true
true
- <!--
A flag indicating if the JBoss Loader should be used. This loader
uses a unified class loader as the class loader rather than the tomcat
specific class loader.


-->
true
- <!--
The name of the request attribute under with the authenticated JAAS
Subject is stored on successful authentication. If null or empty then
the Subject will not be stored.


-->
j_subject
- <!--
*******************************************************
****************** CLUSTERING *************************
*******************************************************
In order to activate HTTP Session clustering for Tomcat
make sure you run JBoss's "all" configuration i.e.
"run -c all"
(the default configuration doesn't contain clustering)

Furthermore, you may change SnapshotMode and
SnapshotInterval attributes below to indicate when to
synchronize changes with the other node(s).

If you use Apache+mod_jk(2) you will most probably use
the AJP1.3 connector below. Thus, if you so wish,
you may comment (i.e. deactivate) the HTTP connector
as it won't be used anymore.

*******************************************************
*******************************************************
*******************************************************


-->
- <!--
If you are using clustering, the following two attributes
define when the sessions are replicated to the other nodes.
The default value, "instant", synchronously replicates changes
to the other nodes. In this case, the "SnapshotInterval" attribute
is not used.
The "interval" mode, in association with the "SnapshotInterval"
attribute, indicates that Tomcat will only replicates modified
sessions every "SnapshotInterval" miliseconds at most.


-->
instant
- <!-- you may switch to "interval"
-->
2000
-
-
-
-

-
- <!-- Access logger
-->

- <!--
This valve clears any caller identity set by the realm
and provides access to the realm about the existence of an
authenticated caller to allow a web app to run with a realm
that support unauthenticated identities. It also establishes
any run-as principal for the servlet being accessed.


-->

- <!-- Default context parameters
-->



- <!-- A HTTP/1.1 Connector on port 8080
-->

- <!-- A AJP 1.3 Connector on port 8009
-->

- <!--
SSL/TLS Connector configuration using the SSL domain keystore





-->



jboss:service=TransactionManager

[gsureshbabu]

hi all
i have been trying to establish clustering with jboss-3.2.3 with two nodes.
1.which properties i have to chnage in the jboss-service.xml in the
jboss-3.2.3/server/default/deploy/jbossweb-tomcat41.sar/META-INF/jboss-service.xml
for clustering.
2. where we will store workers.properties in jboss-3.2.3. for mod_jk+apache
Kindly help me (Urgent)

Thanks
suresh