I did use jboss 3.2.3 (default server) with cocoon 220.127.116.11 as an webapp deployed in a folder (cocoon.war) so far. I used a dynamic class loading mechanismen in cocoon which needed to receive compiled classes from the WEB-INF\lib folder at runtime (Comment for cocoon users: I did use dynamic class loading in javaflow.). This perfectly worked under jboss 3.2.3 always getting the current file deployed under this folder. However, switching to Jboss 4.0.2 with exactly the same webapp, it did not work. What MAJOR changes are there in the two versions concerning dynamic class loading? Thanks for replies. Janis.