We have become very interested in VWS and are trying to migrate our application from Tomcat. As the first step, following the documentation, I dropped our application WAR (which works on Tomcat 6) in the pickup directory. According to the log, VWS installs the WAR, but fails to start it.
[2010-11-14 16:12:05.472] fs-watcher                   <HD0001I> Hot deployer processing 'CREATED' event for file 'EMA-Server.war'.
[2010-11-14 16:12:06.122] fs-watcher                   <DE0000I> Installing bundle 'EMA-Server' version '0.0.0'.
[2010-11-14 16:12:09.285] fs-watcher                   <DE0001I> Installed bundle 'EMA-Server' version '0.0.0'.
[2010-11-14 16:12:09.311] fs-watcher                   <DE0004I> Starting bundle 'EMA-Server' version '0.0.0'.
[2010-11-14 16:12:09.316] Thread-3                     <WE0000I> Starting web bundle 'EMA-Server' version '0.0.0' with context path '/EMA-Server'.
[2010-11-14 16:12:14.696] Thread-3                     <WE0005E> Failed to start web bundle 'EMA-Server' version '0.0.0': consult the serviceability log for further details.
[2010-11-14 16:12:14.701] start-signalling-4           <DE0006E> Start failed for bundle 'EMA-Server' version '0.0.0'. org.eclipse.virgo.kernel.deployer.core.DeploymentException: W
eb application failed to start
        at org.eclipse.virgo.web.core.internal.WebBundleLifecycleListener.onStarted(WebBundleLifecycleListener.java:129)
        at org.eclipse.virgo.kernel.install.artifact.internal.ArtifactStateMonitor.onStarted(ArtifactStateMonitor.java:205)
        at org.eclipse.virgo.kernel.install.artifact.internal.AbstractInstallArtifact.asyncStartSucceeded(AbstractInstallArtifact.java:273)
        at org.eclipse.virgo.kernel.install.artifact.internal.AbstractInstallArtifact.access$0(AbstractInstallArtifact.java:270)
        at org.eclipse.virgo.kernel.install.artifact.internal.AbstractInstallArtifact$StateMonitorSignal.signalSuccessfulCompletion(AbstractInstallArtifact.java:223)
        at org.eclipse.virgo.kernel.core.internal.BundleStartTracker$1.run(BundleStartTracker.java:140)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:619)
Caused by: org.eclipse.gemini.web.core.WebApplicationStartFailedException: org.eclipse.gemini.web.core.spi.ServletContainerException: Web application at '/EMA-Server' failed to sta
rt. Check the logs for more details.
        at org.eclipse.gemini.web.internal.StandardWebApplication.start(StandardWebApplication.java:107)
        at org.eclipse.virgo.web.core.internal.WebBundleLifecycleListener.onStarted(WebBundleLifecycleListener.java:120)
        ... 8 common frames omitted
Caused by: org.eclipse.gemini.web.core.spi.ServletContainerException: Web application at '/EMA-Server' failed to start. Check the logs for more details.
        at org.eclipse.gemini.web.tomcat.internal.TomcatServletContainer.startWebApplication(TomcatServletContainer.java:123)
        at org.eclipse.gemini.web.internal.StandardWebApplication.start(StandardWebApplication.java:90)
        ... 9 common frames omitted 
While searching in the documentation, I came across the following note. It got my attention, as we use the TomcatInstrumentableClassLoader in the Tomcat's context.xml packaged in our WAR file.
 Is TomcatInstrumentableClassLoader  considered a "Custom class loader" in VWS? If yes, is there any workaround for it? Here's the line from our context.xml file: