Spring Boot will serve static resources or my 404 redirection Handler, but not both - spring

Question

I have a Spring Boot app bundled with React, that I am wanting to re-direct all requests that aren't found as static resources back to the index (so React can handle the single-page routing).
Currently, I can serve the static resources or do the 404 redirection, but not both.
Does anyone see any issues with my config?
Static resources are in my Jar at:
classes/static/index.html (etc)
Spring Boot application.yaml config
spring:
main:
allow-bean-definition-overriding: true
mvc:
throw-exception-if-no-handler-found: true
static-path-pattern: /**
resources:
static-locations: classpath:/static
NotFoundResourceHandler.java:
#ControllerAdvice
public class NotFoundHandler {
#ExceptionHandler(NoHandlerFoundException.class)
public ResponseEntity<String> renderDefaultPage() {
try {
InputStream inputStream = new ClassPathResource("/static/index.html").getInputStream();
String body = StreamUtils.copyToString(inputStream, Charset.defaultCharset());
return ResponseEntity.ok().contentType(MediaType.TEXT_HTML).body(body);
} catch (IOException e) {
e.printStackTrace();
return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("There was an error completing the action.");
}
}
}
The above configuration will serve the static resources fine. I've also been able to get it to use the 404 Handler (when I was serving the resources from /, and some other configurations) - but in that case it was using that for every resource, including the JS/CSS/Media files).
Thanks for any help you can provide!
Update:
It's now resolved. I now understand that it's not working because it is mapping every request (/) to the static handler, so that is handling all 404's. I got it to work by mapping the static handler to a specific path (/subdirectory/) and the 404 handler should be thrown for any requests outside of that /subdirectory path (/brokenpath should cause the 404 handler to fire) - which I then set the 404 handler to redirect to /subdirectory/index.html.

Answer 1

Update: It's now resolved. I now understand that it's not working because it is mapping every request (/) to the static handler, so that is handling all 404's. I got it to work by mapping the static handler to a specific path (/subdirectory/) and the 404 handler should be thrown for any requests outside of that /subdirectory path (/brokenpath should cause the 404 handler to fire) - which I then set the 404 handler to redirect to /subdirectory/index.html.