ClassInfo improvements to getMethod (e.g. getMethodExact vs getMethod).Re-add @PathRemainder annotation.
Thrown NotFound causes - javax.servlet.ServletException: Invalid method response: 200

Replace @Bean(findFluentSetters) with @FluentSetters.
HttpResponse should use list of Headers and have a headers(Header...) method.
HttpResponse should allow you to set code.
HttpException subclasses can set status, but does it use code?
HttpException should use list of Headers and have a headers(Header...) method.

JsonSchema should have fluent getters and setters.
Break out @Response bean handling into it's own handler.
Can HeaderGroup be used universally?

@ResponseBody and @ResponseHeaders shouldn't be required on HttpResponse objects.
HttpRuntimeException?
Add ExceptionHeader
REST query/formdata/path parts should extend from PartGroup class.
Eliminate PartSupplier and HeaderSupplier?
Replace ThrowableUtils.assertFieldNotNull() and other methods.