I’ve got a Kotlin library that uses Ktor as a http client. When I’m trying to use it in the Java (Android) project I’m getting a

java.lang.NoClassDefFoundError: Failed resolution of: Lio/ktor/client/features/json/JsonFeature;

exception, even though I can see that library’s pom file contains all of the required dependencies and my consuming app is downloading those dependencies. Library is working well in the Kotlin project. Do I need to add some kind of a configuration to be able to use it from Java app?

how did you include it in your android lib?

Maybe I wasn’t clear enough, so I’ve got a multiplatform library project that contains 2 targets: android and iOS. I’m distributing it separately (not as a multiplatform library), as an Android library via JCenter and as an iOS framework via Cocoapods. When I’m trying to integrate it in Kotlin’s Android app it works well. When I’m trying to integrate it in Java only Android app it compile but it’s failing with the exception I put above

You were clear enough. its just that only including

io.ktor:ktor-client-core

is not enought. You need to specify a specific client for android. either

io.ktor:ktor-client-android

or

io.ktor:ktor-client-okhttp

e.t.c. Now, which one did you include in your gradle build script?

Ah, I’m sorry I didn’t understand the question. So library itself uses:

io.ktor:ktor-client-core
io.ktor:ktor-client-json
io.ktor:ktor-client-logging
io.ktor:ktor-client-serialization
io.ktor:ktor-client-tests
io.ktor:ktor-client-android

All of those dependencies are getting included in the pom file as well

At this point, I would be of more help if I could see your

build.gradle(.kts)

configurations

Sure, here it is: https://github.com/audioburst-labs/AudioburstMobileLibrary/blob/master/build.gradle.kts

Maybe you can try upgrading ktor to latest, I think I had a similar issue

Well, the script looks okay. Maybe just try setting android to target java 1.8? Also try updating ktor to 1.5.1

I tried ktor 1.5.1 and beside that I had to add

packagingOptions {
        exclude("META-INF/ktor-http.kotlin_module")
        exclude("META-INF/ktor-utils.kotlin_module")
        exclude("META-INF/ktor-io.kotlin_module")
        exclude("META-INF/ktor-http-cio.kotlin_module")
        exclude("META-INF/ktor-client-core.kotlin_module")
    }

in a consumer app, it didn’t solve a problem unfortunately

then try android to target java 1.8 Also update your AGP at least go with 4.2.0?

Sure, thanks I will try and get back if it helped

Your Library deps need to be declared as api instead as implementation.

Thank you for suggestions. I applied suggested changes in this commit: https://github.com/audioburst-labs/AudioburstMobileLibrary/commit/21d093c39e15605cb2ad9f18c7d8958859c32ca6 unfortunately it didn’t solve a problem

Could it be because you use jvm and amdroid targets at the same time?

Thanks, I checked it as well and unfortunately it didn’t solve a problem