IMA extension does not work with Java 8 from 2.16.0

Not sure if that is intended, but my Android Studio project (based on Java 1.8) won’t compile with

implementation 'com.google.android.exoplayer:extension-ima:2.16.0'

It works for 2.15.1 and below.

(I’m implementing the IMA player code from https://developers.google.com/interactive-media-ads/docs/sdks/android/client-side into an existing Java project)

from the error listing:

> Task :app:checkDebugAarMetadata FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:checkDebugAarMetadata'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.CheckAarMetadataWorkAction
   > The minCompileSdk (31) specified in a
     dependency's AAR metadata (META-INF/com/android/build/gradle/aar-metadata.properties)
     is greater than this module's compileSdkVersion (android-30).
     Dependency: androidx.core:core:1.7.0.

[tonihei]

I don’t think Java 11 is needed by either IMA or ExoPlayer’s IMA extension. IMA only added this configuration to their demo app (and the linked guide) because Android Studio’s Gradle plugin version 7.0.0 and above requires Gradle to run with Java 11 for compilation (which is also the default in Android Studio since Arctic Fox). They don’t actually have to declare this in their gradle file with targetCompatibility JavaVersion.VERSION_11, as you can verify by removing these lines from their sample app.

I just tested ad playback with ExoPlayer 2.16.1 (and IMA 3.25.1) in a clean app that builds using Java 8 and has only targetCompatibility JavaVersion.VERSION_1_8 defined, and everything is working just fine.

More than one file was found with OS independent path ‘META-INF/annotation-experimental_release.kotlin_module’

I encountered the same problem, which you can fix by adding packagingOptions { exclude("META-INF/*.kotlin_module") } to your gradle project.

[tonihei]

Closing the issue for now as this seems to be an app specific gradle issue.