I think the question is related to the memory leak that happens when a .war is repeatably deployed in a running Tomcat instance. Eventually, you get a out of memory error; generally, "OutofMemoryException: PermGen space" but I get a slightly different behavior on my Mac versus my Linux box.
I read on another forum that this was not specifically a Tomcat problem but a problem with the "cglib".
In any case, even if it's not a Tomcat 5.5 issue I also wonder if Tomcat 6 has managed to work around the problem?
PermGen space errors sometimes occur if you run multiple Web applications in single Tomcat instance, or if your application loads up a lot of classes. The JVM allocates a 64MB memory chunk for the permanent generation heap, which is the heap that holds objects such as classes and methods. When this space gets exceeded, you start getting the PermGen space errors. You would need to increase this setting: Use the -XX:MaxPermSize option in Sun�s JDK to increase the permanent generation heap space. The place to set this would be to edit your catalina.sh/.bat file and add it to the JAVA_OPTS environment variable.