Shows how to serialize-deserialize an object in Scala to a String

serialization.sc

import java.io._
import java.util.Base64
import java.nio.charset.StandardCharsets.UTF_8

def serialise(value: Any): String = {
  val stream: ByteArrayOutputStream = new ByteArrayOutputStream()
  val oos = new ObjectOutputStream(stream)
  oos.writeObject(value)
  oos.close
  new String(
    Base64.getEncoder().encode(stream.toByteArray),
    UTF_8
  )
}

def deserialise(str: String): Any = {
  val bytes = Base64.getDecoder().decode(str.getBytes(UTF_8))
  val ois = new ObjectInputStream(new ByteArrayInputStream(bytes))
  val value = ois.readObject
  ois.close
  value
}

println(deserialise(serialise("My Test")))
println(deserialise(serialise(List(1))))
println(deserialise(serialise(Map(1 -> 2))))
println(deserialise(serialise(1)))

Based on this SO answer, but with bytes Base64 encoding/decoding, which appears to be important, if you serialize to String and back.