Java and Gradle Version Compatibility in Flutter Android Projects

When working with Flutter's Android module, you might encounter the error: "Your build is currently configured to use incompatible Java X.X.X and Gradle X.X.X." This occurs when there's a mismatch between your Java Development Kit (JDK) and Gradle versions.

Understanding the Compatibility Issue

Gradle has specific Java version requirements. Using incompatible versions causes build failures and synchronization issues. The solution involves either:

1. Upgrading Gradle to match your Java version
2. Downgrading Java to match your Gradle version

INFO

Always check the official Gradle-Java compatibility matrix before making changes.

Method 1: Change Gradle Version

Update Gradle Wrapper

Locate and edit gradle-wrapper.properties in your android/gradle/wrapper/ directory:

distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-7.5-all.zip

Common compatible versions:

• Java 11: Gradle 7.0-7.5
• Java 17: Gradle 7.3+
• Java 21: Gradle 8.3+

Update Android Build Gradle

In android/build.gradle, ensure the Gradle plugin version matches:

dependencies {
    classpath 'com.android.tools.build:gradle:7.2.2'
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}

Method 2: Change JDK Version

Using Android Studio GUI

1. Via Project Structure:

   • File → Project Structure → SDK Location
   • Under Gradle Settings, select Gradle JDK
   • Choose a compatible version or download a new JDK

2. Quick Search Method:

   • Press Shift twice (Windows/Linux) or ⇧⇧ (Mac)
   • Type "JDK" and select "Change Gradle JDK Location"
   • Choose the appropriate JDK version

3. Settings Menu:

   • Settings → Build, Execution, Deployment → Build Tools → Gradle
   • Select Gradle JDK and choose a compatible version

Using Embedded JDK

For most Flutter projects, Android Studio's embedded JDK works well:

• Select "Embedded JDK" in the Gradle JDK options
• This ensures compatibility with the current Gradle version

Recommended Approach

Best Practice

For Flutter projects, we recommend using Java 11 with Gradle 7.5 as this combination provides maximum stability and compatibility with most plugins.

Verification and Cleanup

After making changes:

1. Clean your project: Build → Clean Project
2. Rebuild: Build → Rebuild Project
3. Refresh Gradle: Click "Sync Project with Gradle Files"

WARNING

Ensure your Flutter SDK is updated (flutter upgrade) as older versions may have compatibility constraints with newer Gradle/Java versions.

Troubleshooting

If issues persist:

1. Invalidate caches: File → Invalidate Caches / Restart
2. Check compatibility matrix: Verify your specific version combination
3. Review plugin requirements: Some Flutter plugins may have specific Gradle/Java requirements

By following these steps, you should resolve the Java-Gradle compatibility issue and successfully build your Flutter Android project.