Serialization of dynamic Proxies

serialize_Dyn_proxy.scala

//An interface we'll secretly inject into the mix, in order to get Java Serialization to think we've implemented writeReplace
trait Replaceable {
 @throws(classOf[java.io.ObjectStreamException])
 def writeReplace(): AnyRef
}

//An external representation of our Proxy
case class SerializedProxy(...) { //Whatever you need to store away in order to rematerialize
  @throws(classOf[java.io.ObjectStreamException])
  def readResolve(): AnyRef = {
    //Logic to re-appear as a proxy (on potentially a different machine etc)
  }
}

//As always, you want to implement the behavior of your Proxy, and in here we trap the call to writeReplace
class YourInvocationHandler(...) extends InvocationHandler {
  def invoke(proxy: AnyRef, method: Method, args: Array[AnyRef]): AnyRef = method.getName match {
    case "writeReplace" if (args eq null) || args.length == 0 => SerializedProxy(...) //Profit!
    //...toString, equals, hashCode, all other invocations
  }
}

//When you create your Proxy, add Replaceable to the sequence of interfaces to proxy
val serializableProxy = Proxy.newProxyInstance(loader, interfaces :+ classOf[Replaceable], new YourInvocationHandler(...)).asInstanceOf[YourProxiedType]

//And now you can pass your serializableProxy to an ObjectOutputStream like a Boss!