@GetMapping(path = "/instances/{id}", produces = MediaType.APPLICATION_JSON_VALUE)
    public Mono<ResponseEntity<Instance>> instance(@PathVariable String id) {
        LOGGER.debug("Deliver registered instance with ID '{}'", id);
        return registry.getInstance(InstanceId.of(id))
                       .filter(Instance::isRegistered)
                       .map(ResponseEntity::ok)
                       .defaultIfEmpty(ResponseEntity.notFound().build());
    }
@ GetMapping ( path = "/instances/{id}" , produces = MediaType . APPLICATION_JSON_VALUE ) public Mono < ResponseEntity < Instance > > instance ( @ PathVariable String id ) { LOGGER . debug ( "Deliver registered instance with ID '{}'" , id ) ; return registry . getInstance ( InstanceId . of ( id ) ) . filter ( Instance :: isRegistered ) . map ( ResponseEntity :: ok ) . defaultIfEmpty ( ResponseEntity . notFound ( ) . build ( ) ) ; }
Get a single instance.

@param id The application identifier.
@return The registered application.