how to return a long type in java funtion register to v8

I want to return a lang value in a java funtion,what can i do

fun getRandomValues():Long{
val sercurirandom = SecureRandom()
val bytes = ByteArray(4)
sercurirandom.nextBytes(bytes)
val results = bytes.getUIntAt(0)
return results
}

this function by kotlin what can i do to register it to js runtime