Usually you'd make a Java/Kotlin/Whatever class that does the JVM code (e.g. calls out to Android, retrieves the list of files, processes that and prepares the most reasonable subset of data to be passed into Go world) and then use JNI APIs to instantiate it and call it.

(Alternatively, you can instantiate such a proxy class at app startup and pass it into Go world when you call into it for the first time.)