I'm seeing the following in our logs when we try to forward to a JSP:
[2018-03-22 10:43:30,365][XNIO-2 task-15] WARN compiler - JBWEB005037: Failed to delete generated Java file '/tmp/org/apache/jsp/auth/fed/postauthnresp_jsp.class' [2018-03-22 10:43:30,366][XNIO-2 task-15] WARN compiler - JBWEB005037: Failed to delete generated Java file '/tmp/org/apache/jsp/auth/fed/postauthnresp_jsp.java' [2018-03-22 10:43:30,464][XNIO-2 task-15] WARN compiler - JBWEB005037: Failed to delete generated Java file '/tmp/org/apache/jsp/auth/fed/postauthnresp_jsp.java'
and the browser gets a 404. refreshing the browser multiple times (3 to be exact) results in success. The page hasn't changed in multiple years.(https://github.com/TremoloSecurity/OpenUnison/commits/master/unison/open-unison-webapp/src/main/webapp/auth/fed/postauthnresp.jsp) and everything was running fine until this week when we patched the servers. There was no change to the undertow version. We tried disabling selinux, but that didn't change anything.