Problem throwing exceptions inside CompletableFuture run async - spring-boot

Question

I'm working on a microservice app, in service layout I want to invoke with CompletableFuture.runAsync(). The problem is when I want to throw exception, I have my own Handler Exception, but I can't capture error when it is produced in my catch block inside CompletedFuture shown below:
Controller:
#PostMapping(path="/offers/offer")
public CompletableFuture<Oferta> infoPropiedad(#Valid #RequestBody OfertaRequest inDTO) throws
WebServiceBadResponseException, SOAPException, IOException, InterruptedException, ExecutionException {
System.out.println("THREAD: "+Thread.currentThread().getName());
CompletableFuture<Oferta> outTO = new CompletableFuture<Oferta>();
return CompletableFuture.supplyAsync(()->{
try {
return ofertasService.ofertasService(inDTO);
} catch (Exception e) {
System.out.println("Error inesperado en la capa del controlador");
}
return null;
});
}
Service:
CompletableFuture<OfertaCrm> completableFutureCRM =
CompletableFuture.supplyAsync(()-> {
try {
return clientOferta.llamadaWebServiceOfertas(inDTOCrm);
} catch (Exception e1) {
//throw Exception and capture it with my handler class
}
});
ClientWs:
public OfertaCrm llamadaWebServiceOfertas(OfertaRequestCRM inDtoCrm)
throws SOAPException, IOException {
CompletableFuture<OfertaCrm> completableFuture = new CompletableFuture<OfertaCrm>();
logger.info("Iniciamos la llamada al WS");
//Error produces here and I want to controle it and capture with my handler class
Error handler:
#ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
#ExceptionHandler({
WebServiceBadResponseException.class,
SOAPException.class,
IOException.class
})
#ResponseBody
public ErrorMessage internalError(Exception exception) {
return new ErrorMessage(exception,exception.getMessage());
}
I could not be applying the correct form. Any idea how to throw the exception inside the supplyAsync block?

Answer 1

CompletableFuture will wrap the exception thrown within the execution inside a CompletionException. You can handle it by intercepting the root cause exception directly. Below is a simplified example.
Controller:
#RestController
public class SimpleController {
#Autowired
SimpleService simpleService;
#GetMapping("/testing")
public CompletableFuture<Integer> testing(){
return simpleService.doStuff();
}
}
Service:
#Service
public class SimpleService {
public CompletableFuture<Integer> doStuff(){
// 1 / 0 will throw ArithmeticException
return CompletableFuture.supplyAsync(() -> 1 / 0);
}
}
Controller Advice:
#RestControllerAdvice
public class SimpleControllerAdvice {
#ExceptionHandler(ArithmeticException.class)
public String handleCompletionException(ArithmeticException ex){
return "hello world";
}
}
GET /testing
hello world