It is indeed memory leak, but triggered by arquillian servlet protocol testing.
I've send PR with fix described what is going one more in issue you created Undertow Memory Leak · Issue #8263 · wildfly/wildfly · GitHub
I encounter a very similar problem if I repeatedly (manually) redeploy a war containing just a very simple servlet class. So there is no arquillian involved. After each undeploy the servlet class remains in memory. So this should mean there is something wrong with undertow or the way wildfly uses it. Can anyone else confirm this problem?
how are you verifying that class is still loaded?
do you do few full GC cycles before checking for leftover classes
I tried it again, but this time waited longer and forced more garbage collections via yourkit profiler. It seems that i did not wait long enough. After several minutes / garbage collections the servlet object is collected.
Sorry for the false alarm and thank you for your answer!