Async CompletableFuture append errors

I’m not totally sure error comes from problem spring web but if I have a controller with following code:

@PutMapping(value = "/{name}")
public CompletableFuture<User> updateLaboratoryByName(@RequestBody User user) {
    return service.save(laboratory).thenApply(this::toLaboratoryResponse);
}

With basic service

@Async
@Transactional
public CompletableFuture<user> save(User user) {
    if (<SOME CONDITION, WHATEVER>) {
        thrown new IllegalArgumentException("blabla");
    }
    return CompletableFuture.completedFuture(repository.save(laboratory));
}

Both messages will be display on response

{
	"title": "Internal Server Error",
	"status": 500,
	"detail": "java.lang.IllegalArgumentException: blabla"
}{
	"timestamp": "2017-09-25T12:16:50.615+0000",
	"status": 500,
	"error": "Internal Server Error",
	"exception": "java.util.concurrent.CompletionException",
	"message": "java.lang.IllegalArgumentException: blabla",
	"path": "/api/v1/users/XXXXX"
}

[whiskeysierra]

@kakawait I created #119 to enhance the readme. I’m not sure how to fix this programatically.

[whiskeysierra]

We always exclude that one from our applications:

@EnableAutoConfiguration(exclude = ErrorMvcAutoConfiguration.class)

@lukasniemeier-zalando Can you remember why exactly?