While Resin3 claims to be a JSR 45 compliant JSP container our testing was unable to access the JSP-Java sourcemap. Therefore, JSP debugging is not available for this server.
It seems with later releases of the 3.0.x series there have been bug fixes to the JSR 45 implementation, if infact these are now returning a sufficient source map, JSP debugging should work out of the box while using Resin 3.