If you've recently upgraded Android Studio to the Flamingo release and have either run or built an existing Android app, you might have run into an error similar to the following:

Caused by: org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:

The terminal output for this error is similar to the following:

FAILURE: Build failed with an exception.* Where:Build file '…/example/android/build.gradle'* What went wrong:Could not compile build file '…/example/android/build.gradle'.> startup failed:  General error during conversion: Unsupported class file major version 61  java.lang.IllegalArgumentException: Unsupported class file major version 61  at groovyjarjarasm.asm.ClassReader.<init>(ClassReader.java:189)  at groovyjarjarasm.asm.ClassReader.<init>(ClassReader.java:170)  […   …   … 209 more lines of Groovy and Gradle stack trace …   …   …]  at java.base/java.lang.Thread.run(Thread.java:833)

This error occurs because Android Studio Flamingo updates its bundled Java SDK from 11 to 17. Flutter uses the version of Java bundled with Android Studio to build Android apps. Gradle versionsprior to 7.3 can't run when using Java 17.

You can fix this error by upgrading your Gradle project to a compatible version (7.3 through 7.6.1, inclusive) using one of the following approaches.

Upgrade the Gradle version in Android Studio Flamingo as follows:

1. In Android Studio, open theandroid folder. This should bring up the following dialog:

   

   Update to a Gradle release between 7.3 through 7.6.1, inclusive.

2. Follow the guided workflow to update Gradle.

   

Do the following from the top of your Flutter project.

1. Go to the Android directory for your project.

   $cd android

   content_copy

2. Update Gradle to the preferred version. Choose between 7.3 through 7.6.1, inclusive.

   $./gradlew wrapper --gradle-version=7.6.1

   content_copy

The error appears similar toUnsupported class file major version 65. This is an indication that your Java version is newer than the version of gradle you are running can handle. There is a non obvious set of dependencies surrounding AGP, Java, and Gradle.

The easiest way to resolve this issue is to use Android Studio AGP upgrade assistant. To use select your top-levelbuild.gradle file in Android Studio then select Tools -> AGP Upgrade Assistant.

Runflutter analyze --suggestions to see if your AGP, Java, and Gradle versions are compatible. If Gradle needs to be updated you can update it with./gradlew wrapper --gradle-version=SOMEGRADLEVERSION where SOMEGRADLEVERSION is the version (you can use a newer version) suggested byflutter analyze.

To find the Java version being used runflutter doctor. On a mac, you can find the Java versions that the OS knows about with/usr/libexec/java_home -V. To set the version of Java that all flutter projects use runflutter config --jdk-dir=SOMEJAVAPATH where SOMEJAVAPATH is a path to a Java version like/opt/homebrew/Cellar/openjdk@17/17.0.13/libexec/openjdk.jdk/Contents/Home

A few notes to be aware of:

• Repeat this step for each affected Android app.
• This issue can be experienced by those whodon't download Java and the Android SDK through Android studio. If you've manually upgraded your Java SDK to version 17 but haven't upgraded Gradle, you can also encounter this issue. The fix is the same: upgrade Gradle to a release between 7.3 and 7.6.1.
• Your development machinemight contain more than one copy of the Java SDK:
  • The Android Studio app includes a version of Java, which Flutter uses by default.
  • If you don't have Android Studio installed, Flutter relies on the version defined by your shell script'sJAVA_HOME environment variable.
  • IfJAVA_HOME isn't defined, Flutter looks for anyjava executable in your path. Theflutter doctor -v command reports which version of Java is used.
• If you upgrade Gradle to a releasenewer than 7.6.1, you might (though it's unlikely) encounter issues that result from changes to Gradle, such asdeprecated Gradle classes, or changes to the Android file structure, such assplitting out ApplicationId from PackageName. If this occurs, downgrade to a release of Gradle between 7.3 and 7.6.1, inclusive.
• Upgrading to Flutter 3.10 won't fix this issue.