How to implement interface Serializable in scala? -

i have scala class like:

@entity("users") class user(@required val cid: string, val isadmin: boolean = false, @required val datejoined: date = new date() ) {   @id var id: objectid = _        @reference   val foos = new arraylist[foo]      } 

if java class put implements java.io.serializable not work in scala. foos declared above private or public?

scala 2.9.x have interface named serializable, may extends or mixin this. before 2.9.x @serializable choice.