If you are using Railo you will want to make sure you have locked down the uri /railo-context/ - this is Railo's equivilent to ColdFusion's /CFIDE/ directory. It contains the Railo Administrator, as well as some other supporting files and mappings.

Yesterday I gained access to the Google App Engine for Java, early release program, and as any CFML developer would do, I tried getting a CFML server (both Railo and OpenBD) to run on it. I posted some of my experiences on twitter, unfortunately I was unsuccessful.