Does anyone successfully use Hibernate with Kotlin? I'm currently looking for best practices as to how an

Entity

should be defined. It seems a good idea to just use

data

classes. That's probably not the best thing to do though as properties (esp. auto-generated ID) change after an entity has been persisted, which makes the Kotlin-generated equals/hashcode functions yield other results (this is a problem in hashed collections e.g.). Read here: https://stackoverflow.com/questions/1638723/how-should-equals-and-hashcode-be-implemented-when-using-jpa-and-hibernate

Hello all! I want to link two tables across the bridge to the third table. In the bridge table, have a column with the condition (1, 2). And further, when deleting from the first table for example, information from the third table would be deleted too, where condition 1 in the bridge table. Its possible one bridge for two tables? And yeah, i use Kotlin 😛

Hello, does anyone have any examples with TornadoFX, Hibernate and ViewModel?

Is this article outdated? https://kotlinexpertise.com/hibernate-with-kotlin-spring-boot/ I found this article that was updated a couple of months ago, and it doesn't mention any if the issues from the first article. https://www.baeldung.com/kotlin-jpa

I'm having a weird issue with Hibernate. Not sure whether it's Kotlin specific but it seems to be quite generic so I guess Java guys would already complain 🙂 I have this in my

BaseEntity

(from which all other non-embeddable entities in my model inherit):

@Id
    @GeneratedValue
    var id: Long? = null

A framework I'm currently integrating would benefit from having the annotations on the getters instead of fields so I did this:

@get:Id
    @get:GeneratedValue
    var id: Long? = null

Once I do that (and only that) I run into really weird Hibernate errors on the app startup, e.g.

Could not locate setter method for property [com.vacuumlabs.robo.backend.entities.Money#amount]

. Well,

Money#amount

is indeed just a

val

but how is that related to moving the

@Id

annotation to the getter? Moreover,

Money

is exactly an embeddable entity that does not inherit from

BaseEntity

... Okay, so I switch it to

var

and I get another error (from complete different entity):

Unable to create unique key constraint (client_id, iban) on table account: database column 'client_id' not found

. But of course the

client_id

column is there and if I switch the

@Id

back to the property annotation then my app starts and runs ok. I'm afraid I might be running into some generic issue here. Did anyone else encounter this?

Hello, I'currently trying to used Kotlin with Hibernate, and I've found one weird issue with a certain feature of Hibernate. Hibernate has a multi-tenancy feature, and while trying it out, I had an issue with function overrides from the

MultiTenantConnectionProvider

interface. The issue I'm having is with

isUnwrappableAs

and

unwrap

functions:

class TenantSchemaConnectionProvider : MultiTenantConnectionProvider {
    override fun isUnwrappableAs(unwrapType: Class): Boolean {
        TODO("Not yet implemented")
    }

    override fun <T : Any?> unwrap(unwrapType: Class): T {
        TODO("Not yet implemented")
    }

    // the rest of the overrides
}

In this case, the compiler complains with the following error:

One type argument expected for class Class<T : Any!>

. I've tried changing the types to

Class<*>

and

Class<T>

respectively, but that just makes the compiler complain the the functions are not overriding anything, and that the class has missing overrides from the interface. Any idea how to solve this issue?

Ok, the issue does get solved if do:

class TenantSchemaConnectionProvider : MultiTenantConnectionProvider {    
    override fun isUnwrappableAs(@NotNull unwrapType: Class<*>): Boolean {
        return false
    }

    override fun <T> unwrap(@NotNull unwrapType: Class<T>): T? {
        return null
    }
    // ...
}

But, the IDE still complains that it's wrong. The compiler accepts it tho 🤔

I guess this is more of an issue with the Kotlin IDE plugin, I guess I should post this in the relevant channel?