Symptoms

1. Accessing the space via webdav returns a blank page and the log file contains this error:

   
   2009-12-18 17:47:49,186 ERROR [http-8080-1] [[Standalone].[localhost].[/].[servlet-module-container-servlet]] log Servlet.service() for servlet servlet-module-container-servlet threw exception
   java.lang.NullPointerException
   	at com.atlassian.confluence.pages.NaturalStringComparator.compareNatural(NaturalStringComparator.java:75)
   	at com.atlassian.confluence.pages.NaturalStringComparator.compareNatural(NaturalStringComparator.java:57)
   	at com.atlassian.confluence.pages.NaturalStringComparator.compare(NaturalStringComparator.java:42)
   	at com.atlassian.confluence.pages.Page$ChildPositionComparator.compare(Page.java:313)
   	at com.atlassian.confluence.pages.Page$ChildPositionComparator.compare(Page.java:282)
   	at java.util.Arrays.mergeSort(Arrays.java:1270)
   	at java.util.Arrays.mergeSort(Arrays.java:1282)
   	at java.util.Arrays.mergeSort(Arrays.java:1282)
   

2. If you are on older version of Webdav eg. version 1.1 or earlier you may see this error in the log file:

   
   2009-12-17 17:53:16,702 ERROR [http-8080-Processor6] [[Standalone].[localhost].[/].[servlet-module-container-servlet]] invoke Servlet.service() for servlet servlet-module-container-servlet threw exception
   java.lang.NullPointerException
   	at com.atlassian.confluence.extra.webdav.servlet.WebdavURLCodec.hasUnsafeChars(WebdavURLCodec.java:123)
   	at com.atlassian.confluence.extra.webdav.servlet.resource.BaseResource.getPath(BaseResource.java:90)
   	at com.atlassian.confluence.extra.webdav.servlet.resource.BaseCollectionResource.getPath(BaseCollectionResource.java:59)
   	at com.atlassian.confluence.extra.webdav.servlet.resource.WebdavResourceServlet.makeAbsoluteURI(WebdavResourceServlet.java:752)
   	at com.atlassian.confluence.extra.webdav.servlet.resource.WebdavResourceServlet.addHrefElement(WebdavResourceServlet.java:744)
   	at com.atlassian.confluence.extra.webdav.servlet.resource.WebdavResourceServlet.appendPropResponses(WebdavResourceServlet.java:407)
   

3. List Pages Tree View Loads Forever.
4. Other spaces work fine.

Cause

When accessing a functionality that requires page title comparison, Confluence will throw a NullPointerException if the page title happens to be null.

Resolution

To identify the page title(s) that is null,