I figured it out. For the curious, I was specifying a loader for my root context, but
that wasn't being propogated to any WAR files, only to servlets explicitly added to
the root context at startup time. I had to set the parent classloader on the host
which was loading the WAR files.
Rich
> -----Original Message-----
> From: Richard Unger
> Sent: Monday, April 01, 2002 4:36 PM
> To: '[EMAIL PROTECTED]'
> Subject: Classloader issue with Embedded tomcat and WAR deployment
>
>
> I'm making a tomcat 4.0.3 module for netbeans, and I'm
> running into an odd problem with the
> org.apache.catalina.loader.WebappClassLoader.
>
> I'm utilizing the Embedded class to build my server, and I'm
> using the HostConfig mechanism for rolling in WAR files. I
> have no trouble loading individual servlets, but when I start
> the server with a WAR file in place, I get a
> NoClassDefFoundError: javax/servlet/http/HttpServlet. The
> error is masked by a catch( Throwable t) clause in
> HostConfig::deployApps, but when I explicitly print the stack
> trace, it looks like:
>
> java.lang.NoClassDefFoundError: javax/servlet/http/HttpServlet
> at java.lang.ClassLoader.defineClass0(Native Method)
> at java.lang.ClassLoader.defineClass(ClassLoader.java:493)
> at
> java.security.SecureClassLoader.defineClass(SecureClassLoader.
> java:111)
> at
> org.apache.catalina.loader.WebappClassLoader.findClassInternal
> (WebappClassLoader.java:1631)
> at
> org.apache.catalina.loader.WebappClassLoader.findClass(WebappC
> lassLoader.java:926)
> at
> org.apache.catalina.loader.WebappClassLoader.loadClass(WebappC
> lassLoader.java:1360)
> at
> org.apache.catalina.loader.WebappClassLoader.loadClass(WebappC
> lassLoader.java:1243)
> at
> org.apache.catalina.core.StandardWrapper.loadServlet(StandardW
> rapper.java:865)
> at
> org.apache.catalina.core.StandardWrapper.load(StandardWrapper.
> java:808)
> at
> org.apache.catalina.core.StandardContext.loadOnStartup(Standar
> dContext.java:3266)
> at
> org.apache.catalina.core.StandardContext.start(StandardContext
> .java:3395)
> at
> org.apache.catalina.core.ContainerBase.addChild(ContainerBase.
> java:785)
> at
> org.apache.catalina.core.StandardHost.addChild(StandardHost.java:454)
> at
> org.apache.catalina.core.StandardHost.install(StandardHost.java:723)
> at
> org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:331)
> at
> org.apache.catalina.startup.HostConfig.start(HostConfig.java:398)
> at
> org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConf
> ig.java:232)
> at
> org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(L
> ifecycleSupport.java:156)
> at
> org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1131)
>
> at
> org.apache.catalina.core.StandardHost.start(StandardHost.java:614)
> at
> org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1123)
>
> at
> org.apache.catalina.core.StandardEngine.start(StandardEngine.java:343)
> at
> org.apache.catalina.startup.Embedded.start(Embedded.java:957)
> at
> org.netbeans.modules.httpserver.TomcatServer.start(Unknown Source)
> at
> org.netbeans.modules.httpserver.HttpServerModule$1.run(Unknown Source)
>
>
> Delving into StandardWrapper line 865, I see the classloader
> attempting to load the servlet residing in the WAR file.
> This servlet extends HttpServlet, and that's where my error
> is coming from. However, if I stick in a line:
>
> classLoader.loadClass("javax.servlet.http.HttpServlet")
>
> before line 865, everything works fine. I'm guessing this is
> because HttpServlet gets loaded in an earlier run of
> StandardWrapper::loadServlet() (like when the DefaultServlet
> gets loaded).
>
> Must I explicitly set the parent classloader for the
> org.apache.catalina.loader.WebappLoader? How?
>
>
> Rich
>
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