Stupid question, but is it possible to compile against Java 12 (Java 11 is working):

compileOptions {
        sourceCompatibility = JavaVersion.VERSION_12
        targetCompatibility = JavaVersion.VERSION_12
    }

    kotlinOptions {
        jvmTarget = "12"
    }

I get Unsupported class file version: 56. AS: 4.1 C5 Gradle: 6.3 Kotlin: 1.3.72 JDK: 14.0.1 When I'm searching for "android java 12/13 support" I find sources that claim gradle/kotlin/IntelliJ is supporting both so did I miss something or is it just not supported yet?

From my understanding, Android only supports up to Java 8 (partially) right now: https://developer.android.com/studio/write/java8-support

You can set kotlin to target as high as 11. D8 will reject 12+, for now (see https://issuetracker.google.com/issues/141587937). Setting the Java version higher than 8 changes how javac compiles which removes the bootclasspath argument that Android relies on to link against the android.jar from the Android SDK (see https://issuetracker.google.com/issues/139013660)

That is exactly what I'm looking for, thanks boss. Nice overview btw @jw But why can I run my app with java source/target 11 properly. Shoudln't it fail?

are you on an old version of Gradle?

I have the latest one, 6.3.

It shouldn't work. There's example projects in that repo which demonstrate it. Are you referencing Android APIs or is the project empty? It'll look like it works if you're not referencing Android APIs anywhere.

This is currently working for me:

compileOptions {
    sourceCompatibility = JavaVersion.VERSION_11
    targetCompatibility = JavaVersion.VERSION_11
}

kotlinOptions {
    jvmTarget = "11"
}

AS: 4.1 C5 Gradle: 6.3 Kotlin: 1.3.72 JDK: 14.0.1

do you have any Java source files?

No, only kt and kts files

so you'll only have the BuildConfig generated which doesn't reference any Android APIs

Ah ok, so is it right that I dont have to define java source/target because I have no java source files?

it still compiles the BuildConfig, but otherwise is unused, yes

ok thanks!