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From Chris Dailey <mo...@intranet.org>
Subject Improving problem reporting
Date Fri, 28 Oct 2011 19:24:37 GMT
PROBLEM DESCRIPTION:

I have an exception (appended below), and I think it would be nice to 
have more information about what is going on.

If I had more context, it would help me find the cause of my problem 
much more quickly.  For example, if the exception indicated what the 
file/resource that was having the problem was, it would speed up 
troubleshooting immensely.

HOW TO REPRODUCE:

In a JAR file contained in WAR file's WEB-INF/lib folder:  Change the 
MANIFEST.MF file in the JAR file.  Put in a line with ONLY 
"Class-Path:".  Note there is no space after the period, which is what 
causes the error.  During load of the application, the exception which I 
have appended at the end of this message will show up.

SUGGESTED IMPROVEMENT:

My suggestion would be to modify 
ExtensionValidator.validateApplication(...), around line 195.  This is 
the location that actually knows about what the resource is.  It would 
be nice if the IOException was caught, and information about the 
Resource was added to the exception, probably by wrapping the exception.

Because I have not gone through the overhead of getting a version of 
Tomcat running from source, these changes have not been compiled and 
tested, but I think the suggestion is relatively straight-forward.

Here are the suggested code changes:

First code change - move the definition of "resource" outside of the 
try/catch:

         // Locate the Manifests for all bundled JARs
         Resource resource = null; // ADDED
         NamingEnumeration<Binding> ne = null;

Second code change - make the existing declaration of "resource" just an 
assignment:

                 resource = (Resource) obj; // MODIFIED
                 inputStream = resource.streamContent();
                 Manifest jmanifest = getManifest(inputStream);

Third code change: add a catch clause and re-throw:

         } catch (NamingException nex) {
             // Jump out of the check for this application because it
             // has no resources
         } catch (IOException ioex) { // ADDED
             throw new IOException("validation problem in " + 
resource.toString(), ioex); // ADDED
         } finally {

The problem is that the resource may not have a proper toString().  I 
would suggest changing FileDirContext:898 (inner class=FileResource) to 
have a toString method, something along the lines of:

         public String toString() { // ADDED
             return file == null ? "null" : file.toString(); // ADDED
         } // ADDED

Finally, here's the exception:

28-Oct-2011 11:03:03 AM org.apache.catalina.core.StandardContext 
startInternal
SEVERE: Error in dependencyCheck
java.io.IOException: invalid header field
     at java.util.jar.Attributes.read(Attributes.java:410)
     at java.util.jar.Manifest.read(Manifest.java:199)
     at java.util.jar.JarInputStream.<init>(JarInputStream.java:83)
     at java.util.jar.JarInputStream.<init>(JarInputStream.java:60)
     at 
org.apache.catalina.util.ExtensionValidator.getManifest(ExtensionValidator.java:394)
     at 
org.apache.catalina.util.ExtensionValidator.validateApplication(ExtensionValidator.java:195)
     at 
org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5037)
     at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:148)
     at 
org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1033)
     at 
org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:774)
     at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:148)
     at 
org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1033)
     at 
org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:291)
     at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:148)
     at 
org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
     at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:148)
     at 
org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:727)
     at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:148)
     at org.apache.catalina.startup.Catalina.start(Catalina.java:621)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at 
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
     at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
     at java.lang.reflect.Method.invoke(Method.java:616)
     at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:322)
     at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:450)

(And if only java.util.jar.Attributes.read reported WHICH attribute had 
the problem, we'd really be in business.)

Regards,
Chris

-- 
The Time Is The Time!
Daylight Savings Time wastes energy and money


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