kotlinlang #spring

So I have a possibly interesting issue. I'm using @Around advice to call some legacy code which eventually ends up calling new functionality implemented in Kotlin. I use the proceeding join point in the advice to get an array of the args java classes. The method with the around advice is called with a non-nullable boolean but the java class of the argument in ProceedingJoinPoint is java.lang.Boolean. The legacy code then calls a service method written in Kotlin using Class.getMethod(String name, Class<?>... parameterTypes). The problem is that the Kotlin service method has a non-nullable Boolean in it's signature which means it's the primitive type in Java but in the aspect the Java class is java.lang.Boolean. This causes getMethod to fail since it can't find a method matching the signature. Anyone have any ideas on this one? Does this seem like something going on with Spring AOP or something entirely different?

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fun updateEnrollment(enroll: Boolean) {
  // The method with the around advice is called with what should be a primitive boolean since it's not nullable
  service.updateEnrollment(enroll)
}

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@Around(value = "@annotation(replicate)")
fun wrapCall(pjp: ProceedingJoinPoint, replicate: Replicate) {
  val args = pjp.args
  // it.javaClass returns java.lang.Boolean instead of the primitive type
  val argClass = pjp.args.map { it.javaClass }.toTypedArray()
  ...
}

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// getMethod fails because the type is java.lang.Boolean but the method signature is a boolean primitive
service.getClass().getMethod(methodName, types);

dh44t

10/28/2016, 11:27 PM

What happen if you change from non-nullable to nullable? Just for the sake of testing

michael.barker

10/29/2016, 4:14 PM

It works when I do that or swap out the object type to primitive in the aspect so that the getMethod call matches the signature. Then of course that would fail if the signature had a nullable type.

michael.barker

10/29/2016, 4:18 PM

Rather than make parameters nullable I'd probably just make the API such that it doesn't have primitives as parameters or force all primitives to be non-nullable and replace them with the primitive type in the aspect. Wish I didn't have to do a hack though.

starbuxman

11/01/2016, 9:50 PM

hi, whats the right way to instantiate a ParameterizedTypeReference in Kotlin?

starbuxman

11/01/2016, 9:51 PM

in java, u’d say ParameterizedTypeReference <Foo<Bar>> ptr = new ParameterizedTypeReference <Foo<Bar>> () { /* anonymous subclass */ } ;

starbuxman

11/01/2016, 9:51 PM

but its complaining that the constructor is protected in kotlin.

michael.barker

11/01/2016, 9:55 PM

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val ref = object : ParameterizedTypeReference<Foo<Bar>>()  {}

nfrankel

11/02/2016, 7:45 AM

@starbuxman welcome here good sir i wasn’t aware you were a kotlin enthusiast that’s good!

nfrankel

11/02/2016, 7:47 AM

by the way, your question belongs more to the #general channel than here that’s not specific to #spring

roborative

11/04/2016, 4:37 PM

This question is specific to Spring Integration. I'm seeing an exception when trying to serialize error messages:

Caused by: java.io.NotSerializableException: kotlin.reflect.jvm.internal.KParameterImpl

roborative

11/04/2016, 4:39 PM

I'm thinking that possibly changing the message converter for the AMQP channel might do the trick but thought I'd ask here if there's another solution that comes to mind.

roborative

11/04/2016, 4:58 PM

I changed the channel type to JSON but same basic issue -- it' can't convert it.

dh44t

11/04/2016, 6:53 PM

Which kind of object are you trying to serialise?

roborative

11/04/2016, 6:57 PM

It's an ErrorMessage. I believe the

payload

is what can't be serialized.

dh44t

11/04/2016, 6:58 PM

which kind of payload is?

dh44t

11/04/2016, 6:58 PM

it could be a bug on Kotlin, so you could report it om YT

roborative

11/04/2016, 6:59 PM

I think it's an exception

roborative

11/04/2016, 7:00 PM

So really something inside the exception is problematic from a serialization perspective (the

cause

is my guess)

roborative

11/04/2016, 7:01 PM

I've seen it in production for our app and need to figure out a way to reproduce it locally.

miha-x64

11/12/2016, 6:50 PM

Hmm, I have a question… For example, I've got a model:

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@Entity
public class Something {
    @Id
    @GeneratedValue(generator = "uuid2")
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    public UUID id;

    @NotNull @Column(columnDefinition = "TEXT")
    public String text;
}

, a form with the only field

text

, and a controller method:

String addSomething(@ModelAttribute Something something) { somethingRepository.save(something); }

If a user adds

id=00000000-0000-0000-0000-000000000000

to his request, and a model with such id already exists, will Hibernate update an existing model? How we can close this security hole? ~~Actually, we could null out all fields that are not in the form, but it is awful.~~

michael.barker

11/12/2016, 7:02 PM

Sounds like you might want to decouple your contract from your repository.

miha-x64

11/12/2016, 7:04 PM

`public class HttpSomething { public String text; }`;

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@Entity
public class Something {

    protected Something() { }

    public Something(HttpSomething source) {
        …

michael.barker

11/12/2016, 7:05 PM

You'd probably want a SomethingRequest or whatever you want to call it that gets mapped to your entity which is then saved. Maybe there's a better way but that's the approach I'd probably end up taking.