Flutter mek_stripe_terminal ^3.8.0 Causes Build Failure with Unsupported Class File Major Version 65

Below is a breakdown of the error and some troubleshooting steps:

What the Error Means

• Unsupported class file major version 65:
  This indicates that the Jackson core JAR (version 2.16.1) was compiled for a newer Java version (Java 21) that isn’t recognized by your current Android Gradle plugin’s Jetifier. Jetifier is trying to transform the library but can’t handle class files compiled with a class file version it doesn’t support.

• Jetifier Transformation Failure:
  The error occurs during the Jetifier transformation step. Jetifier is used to convert third-party libraries to be compatible with AndroidX. When it encounters an unsupported class file version, the build fails.

Possible Solutions

1. Downgrade the Dependency:
   If possible, try using an earlier version of the dependency (or one compiled for an older Java version) that is compatible with your environment.

2. Update Your Build Tools:

   • Android Gradle Plugin:
     Check if there is an updated version of the Android Gradle plugin that better supports newer Java class file versions.
   • JDK Version:
     Ensure that the JDK you’re using for the build supports the same Java version as the dependency. Running a version that is too old might cause this error.

3. Adjust Your Project’s Java Version:
   You might want to configure your project to use a newer JDK that supports class file major version 65. However, check that all your dependencies and build tools are compatible with that JDK.

Quick Checks

• Verify Your JDK version:
  Run the following command in your terminal:

  BASHCopied
  java -version

  Ensure your JDK is recent enough if you intend to work with libraries compiled with Java 21.

• Review Gradle Settings:
  In your project's build.gradle files, verify the Java/Kotlin compile settings and Gradle plugin versions. For example:

  GROOVYCopied
  android {
      compileOptions {
          sourceCompatibility JavaVersion.VERSION_17
          targetCompatibility JavaVersion.VERSION_17
      }
  }

  You may need to experiment with a higher version if your tools support it.

Final Note

Since the error surfaces when implementing mek_stripe_terminal: ^3.8.0, it may be that this version of the Stripe Terminal integration (or one of its dependencies) is using libraries compiled for a newer Java version than your environment supports. Adjust the dependency version or update your build environment accordingly.

If you continue to experience issues, consider checking the Android Issue Tracker for similar reports or filing a new issue with a full stack trace.