I'm trying to use the getHeader() method of an HttpServletResponse, Intellij doesn't highlight anything but kotlin refuses to compile, claiming getHeader is unresolved. How do I fix this?

Is there any way to get kotlin stdlib version at runtime? Does it have some constant with the version number?

runBlocking {
foo() //foo returns a value and is being captured by the lambda
}

Since runBlocking needs to return void, I get a compiler error

I'm trying to call https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CompletableFuture.html#exceptionally-java.util.function.Function- from Kotlin using a lambda:

exceptionally { 
    it.printStackTrace()
}

But it complains

Type mismatch. Required: Void! Found: Unit

. Shouldn't have Kotlin handled this properly or am I missing something?

The compiler is throwing a KotlinNullpointerException when trying to compile some of my classes... What should I do? x.x

Need help with Kotlin-Java interop!

//Tasks.kt
abstract class Foo : Callable<Unit> {   
    override fun call() { bar() }
    abstract fun bar()
}

//Manager.java
public class FooChild extends Tasks.Foo {
    @Override public void bar() { //haha }
}

Class FooChild is highlighed as Error with message: 'call()' in 'Tasks.Foo' clashes with 'call()' in 'java.util.concurrent.Callable'; attempting to use incompatible return type

Why did the language designers decide to use :: though, instead of just .

how do you make a property reference with that?

is there a way to conditionally invoke a nullable receiver function?

Did someone try the new type inference? Did you encounter issues or is it stable?

Hey! Is it possible to create an

CPointer<BooleanVar>

without the use of the nativeHeap. I would like to create one on the stack, but everythin i've tried failed. Currently im using this

val flag = nativeHeap.alloc<BooleanVar>(); flag.usePinned { it.get().ptr /* <- CPointer<BooleanVar> */}

Hi, is there a password encrypting library like bcrypt

is there a way to turn a type parameter with upper bound

Any?

into its non-nullable variant? I would like to avoid something like:

fun <T: Any> foo(t: T?)

Sorry, I'm not sure which channels is appropriate for this question, please redirect if there's a better place. We're building a backend webservices using Spring Boot + Kotlin and consumes different artifacts with domain models (mixed Java and Kotlin sources). I'd like to make it as easy as possible for our frontend development to consume the API and is looking into putting out a TypeScript-klient as part of the project or at least TypeScript-definitions. Has anyone done something similar and can give any pointers to good tools to use to convert Java/Kotlin-classes to TypeScript-definitions? Only thing I've found so far is https://github.com/ntrrgc/ts-generator

you're adding a void?

Hey, quick recommendation question. Embedded DBs? I want something simple, file based, could be key/value or more complex. Ideally it would let me serialise custom objects automatically. Nitrite+Potassium Nitrite seemed perfect, but I'm getting way too many dependency conflicts due to using apache spark in the same project (jackson is being a pain to get right in terms of versions, which breaks all the serialisation for NO2) This is basically a project that I'm converting form Scala to Kotlin. The scala version used SQLite with an ORM, which is a perfectly reasonable slution. In which case, is there an ORM you'd recommend? Sorry, this ended up being longer than I expected 😂

How to use

@JvmDefault

with Gradle?

Hi all. Could somebody explain why I get this message during Maven build:

[WARNING] Runtime JAR files in the classpath should have the same version. These files were found in the classpath:
    C:/Users/somebody/.m2/repository/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.3.21/kotlin-stdlib-jdk8-1.3.21.jar (version 1.3)
    C:/Users/somebody/.m2/repository/org/jetbrains/kotlin/kotlin-stdlib/1.2.41/kotlin-stdlib-1.2.41.jar (version 1.2)
    C:/Users/somebody/.m2/repository/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.2.41/kotlin-stdlib-jdk7-1.2.41.jar (version 1.2)
[WARNING] Some runtime JAR files in the classpath have an incompatible version. Consider removing them from the classpath

In Maven dependencies I see only this with 1.2.41 version:

[INFO] +- org.jetbrains.kotlin:kotlin-stdlib-jdk8:jar:1.3.21:compile
[INFO] |  +- org.jetbrains.kotlin:kotlin-stdlib:jar:1.2.41:compile
[INFO] |  |  \- org.jetbrains:annotations:jar:13.0:compile
[INFO] |  \- org.jetbrains.kotlin:kotlin-stdlib-jdk7:jar:1.2.41:compile

With coroutines, what is the one-to-many synchronization primitive? Basically I have a game loop, and a number of client coroutines which use select {}. When the game loop completes a cycle, I want to wake up all the clients. I could have the game loop wake up clients one by one, but I was wondering if there’s a better way.

@Travis Griggs “The opt-in can be given in two ways: - either annotate the code element that uses unsigned types with the @UseExperimental(ExperimentalUnsignedTypes::class) annotation - or specify -Xuse-experimental=kotlin.ExperimentalUnsignedTypes compiler option”

So my earlier question boils down to - is there a one-to-many synchronization primitive that I can repeatedly select {} on? I need many coroutines waiting on a single event

Hmm, anyone have experience with Kotlin, Java and Jackson with custom serializer? Mine seems to not match the types I've provided and I'm a bit baffled as to why.

@Iaroslav Postovalov wtf man. not cool

I think this was discussed before, but there's no way to inherit a companion object, right? For instance, I need that every

Model

class have a

Factory

for it

if I have a var lateinit, can I override the getter to provide a default later? not sure where exactly the non null check in the lateinit will be performed, it seems to be on access

Isn't there an annotation or something i can use to tell the compiler to smart-cast

Connection

to not null?

private val Connection?.isUsable get() = this != null && !isClosed

Hi we are doing school object oriented project so we have to draw uml diagram.Would you recommend free uml tools?Uml stands for Unified Modeling Language.

how_come_i_can_use_java_interfaces_here_but_not_kotlin_interfaces_.kt

sealed class BaseViewEffect{
    object ShowView : BaseViewEffect()
}

sealed class ChildViewEffect : BaseViewEffect {
    
}

anyone can help me to achieve inheritance for sealed class

Hey guys, anyone knows how can I check if a lateinit var is initialized from a function of the same class where the lateinit var resides?