Error:Jack is required to support java 8 language features [duplicate]

Question

When I tried to update my android project to use Java 8 after getting android studio 2.1 and android N SDK by adding

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

I had this error

Error:Jack is required to support java 8 language features. Either enable Jack or remove sourceCompatibility JavaVersion.VERSION_1_8.

What should I do?

Erwin

show build.gradle file – Loquacity

See #36880615 – Grannie

Answer 1

Error:Jack is required to support java 8 language features. Either enable Jack or remove sourceCompatibility JavaVersion.VERSION_1_8.

The error say that you have to enable Jack.

To enable support for Java 8 in your Android project, you need to configure your build.gradle file like that

android {
  ...


  compileSdkVersion 23
  buildToolsVersion "24rc2"
  defaultConfig {
  ...
    jackOptions {
      enabled true
    }
  }

  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
} 

Loquacity

After adding the following line I get Error:A problem occurred configuring project ':app'. – Febrific

@AdityaKamath post your problem in new question so I can help you. – Loquacity

Adding retroLambda solved that problem for me. github.com/evant/gradle-retrolambda – Horotelic

Does this work with annotation processing, or would it break compilation? – Brose

Luckily we won't need this in a few weeks. Android will have full support for Java 8 language features. Jack will be deprecated. More details here: android-developers.googleblog.com/2017/03/… – Nebulous

Jack is no longer required. See this: developer.android.com/studio/preview/features/… – Brose

@Brose Were you able to remove jackOptions and still get Java 8 to work? – Covell

@Covell At this point, Java 8 works without Jack. – Brose

@Brose If I remove the jackOptions block from my Gradle, it still throws an error. Are you using retroLambda? – Covell

@Covell Not using any of the legacy plugins. Read: developer.android.com/studio/write/java8-support.html – Brose

To avoid Jack just update your Gradle to 3.0.0-beta1 . Built-in support for Java 8 libraries and certain Java 8 language features. Jack is no longer required, and you should first disable Jack to use the improved Java 8 support built into the default toolchain. . check this one developer.android.com/studio/build/gradle-plugin-3-0-0.html – Pibroch

Did anyone got this error :transformClassesWithPreJackPackagedLibrariesForDebug after adding jack ? – Willard

@BiswasKhayargoli Yes i got that issue "transformClassesWithPreJackPackagedLibrariesForDebug". Any fixes for it? – Sunlight