Still can't register custom exception handlers

It's not possible to register custom exception pages for GrailsExceptionResolver since exceptions are wrapped as org.codehaus.groovy.runtime.InvokerInvocationException. But if you add this at the top of GrailsExceptionResolver.resolveException():

if (e instanceof InvokerInvocationException) {
   e = (Exception)getRootCause(e);
}

then the exception mappings will use the real exception to lookup the page to use.

See this thread for discussion: http://www.nabble.com/Custom-exception-handling---GrailsExceptionResolver-generating--NullPointerException-td25206893.html