How do I resolve error message: "Inheritance from an interface with '@JvmDefault' members is only allowed with -Xjvm-default option"

Issue

I'm new to Android development and I'm currently building my first real app. I'm trying to implement a MVVM architecture and because of that I'm having a viewModel for each fragment and each viewModel has a viewModelFactory. At least, this is how I understood it has to be.

I use the boilerplate code everyone seems to use for the factory:

class ExampleViewModelFactory(private val exampleDao: ExampleDao) : ViewModelProvider.Factory {
    override fun <T : ViewModel> create(modelClass: Class<T>): T {
        if (modelClass.isAssignableFrom(exampleViewModel::class.java)) {
            @Suppress("UNCHECKED_CAST")
            return ExampleViewModel(exampleDao) as T
        }
        throw IllegalArgumentException("Unknown ViewModel class")
    }
}

Now the problem is, that the compiler is giving me the following error:

e: C:\Users\ ...\ExampleViewModel.kt: (64, 7): Inheritance from an interface with '@JvmDefault' members is only allowed with -Xjvm-default option

And this error is produced by the viewModelFactory class I have implemented in the viewModel. I really can't tell what this means and I cant find anything helpful or even related to my specific problem. I basically followed some basic tutorials about creating your first app, but I keep on running into errors like this. In most cases, I was able to fix the problem by myself, but this time it's different.

I know that a lot of you have a lot of experience and knowledge, so I hope that some of you find the time to help me and give me a hint what I can do to fix this.

Solution

It seems like you are either directly or indirectly (through some other library) depending on Lifecycle 2.5.0-alpha01.

As per this issue:

You need to temporarily add following to your build.gradle:

tasks.withType(KotlinCompile).configureEach {
    kotlinOptions {
        freeCompilerArgs += [
                "-Xjvm-default=all",
        ]
    }
}

Note that in certain circumstances you may want to use all-compatibility instead of all, learn more about that in Jebrain's blogpost.

Starting with kotlin 1.6.20 you won't need touch build.gradle for more information see KT-47000

Answered By - ianhanniballake