this Problem is bugging me for some time now and I am running out of options.
I am developing a rather large-for-one-person application based on Seam 2.2.2, Glassfish 2.1, JSF 1.2, Richfaces and Hibernate. For some time now, I am receiving exception reports from Users, all containing a NPE at org.apache.coyote.tomcat5.CoyoteRequest.removeAttribute(CoyoteRequest.java:1749). These exceptions occur on random pages and actions. The stack trace only lists one javassist'ed class created by myself - a custom identy class (SAMSIdenty) extending org.jboss.seam.security.Identity in order to provide a more domain specific permission system. The method called is Identity.getCredetentials(), which I did not override.
The exceptions occur notably more often when redeploying the application without undeploying before or restarting glassfish afterwards. I randomly clicked some pages in the application provided CMS for testing purposes once and it happened every 10-20 requests then. Under normal circumstances it happens way less often. The NPE is not related to the CMS, it also happens with normal .xhtml-Facelets in the admin backend. The CMS provides Facelets from a database using a custom ResourceResolver. Notably, these pages mostly don't rely on any backing beans or non JSF-core taglibs, so I think they can also be ruled out.
The application is deployed several times on the same AS within different context roots and with different configurations for different customers.
Here is a stack trace of one error report, others are similar:
I am not really sure, if this issue is seam related, but high up in the stack trace are many calls to Component.java so this is my best guess.
Many thanks in advance, I am grateful for any advice!