Cause: superclass access check failed: class butterknife.compiler.ButterKnifeProcessor$RScanner

 I've modified my ancient project's gradle.properties file like this:

org.gradle.jvmargs=-Xmx2560m \
--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED \
--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED \
--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED

And now it builds with latest Gradle (8.6 RC3), JDK 21 and latest Android Gradle Plugin (8.2.2)! 🎉