How do I display the Confluence system classpath?

At times, you may see an error like this:

1
2
java.lang.NoSuchMethodError: org.apache.commons.fileupload.servlet.ServletFileUpload.setFileSizeMax

Cause: The Java classpath has another module (JAR) somewhere that overrides the one shipped with Confluence.

Solution:

1. Check for duplicate JARs by going to the following URL:

   1
   2
   http://path-to-confluence/admin/classpath.action
   

   The page lists all modules available to the class loader

2. Scroll to the bottom of the page to make sure that there are no duplicate JARs, as indicated by the following message:

   "No duplicate class files found in classpath JARs"

Resolve duplicate JARs if necessary.