First time JBoss AS and web applications are started after install, following 2 exceptions/errors are reported. The reason for the 1st error is missing jar while JSP file A is compiled and TagLibCache is build as of first access. The reason for the second error is an attempt to access TLD in TagLibCache from JSP file B, while the cache is un-initialized and is missing the TLD definition.
The problem manifests itself with exploded EAR file - preferred way of work by our developers. The workaround is to restart the AS which is undesirable. Here is suggested fix to the org.jboss.web.tomcat.tc5.jasper.TagLibCache class that resolves the issue.