Scala & Objectify4: http://thoughtsofthree.com/2012/04/scala-objectify4/

Annotations.scala

import com.googlecode.objectify.annotation
import scala.annotation.target.field

object Annotations {
  
  type AlsoLoad = annotation.AlsoLoad @field
  type Embed = annotation.Embed @field
  type Id = annotation.Id @field
  type Ignore = annotation.Ignore @field
  type IgnoreLoad = annotation.IgnoreLoad @field
  type IgnoreSave = annotation.IgnoreSave @field
  type Index = annotation.Index @field
  type Load = annotation.Load @field
  type Mapify = annotation.Mapify @field
  type Parent = annotation.Parent @field
  type Serialize = annotation.Serialize @field
  type Translate = annotation.Translate @field
  type Unindex = annotation.Unindex @field
  
}

App.scala

// Create the company
val company = Company("Apple", Address("Infinite Loop", "1", "Cupertino", "United States"))
// Save it synchronous (by adding .now)
val company_key = Ofy.save.entity(company).now
// Create the User (with reference to the company)
val user = new User("steve.jobs@apple.com", "iPassword", "Steve Jobs", Ref.create(company_key))
// Save it synchronous
Ofy.save.entity(user).now

// Retrieve based on the email-adress
val get = Ofy.load.`type`(classOf[User]).id(user.email).get
    

AppBetter.scala

val get = Ofy.load.kind(classOf[User]).id(user.email).get

List of wrappers

LoaderWrapper
ObjectifyWrapper
QueryResultIteratorWrapper
QueryWrapper
SimpleQueryWrapper
TransactionWrapper
ResultWrapper
SimpleFutureWrapper

Ofy.scala

object Ofy extends Ofy {
  
  ObjectifyService.register(classOf[User])
  ObjectifyService.register(classOf[Company])
  
  protected val _conn = new DynamicVariable[Objectify](null)
  
  def ofy: Objectify = {
    if (_conn.value == null) {
      _conn.value = ObjectifyService.factory.begin()
      _conn.value.setWrapper(this)
    }
    
    _conn.value
  }

}

OfyTrait.scala

trait Ofy extends Objectify {
  
  def ofy: Objectify
  
  def load: ScalaLoader = new ScalaLoader(ofy.load)
  def save: Saver = ofy.save
  def delete: Deleter = ofy.delete
  def getTxn: Transaction = ofy.getTxn
  def getFactory: ObjectifyFactory = ofy.getFactory
  def consistency(policy: Consistency): Ofy = new OfyWrapper(ofy.consistency(policy))
  def deadline(value: java.lang.Double): Ofy = new OfyWrapper(ofy.deadline(value))
  def cache(value: Boolean): Ofy = new OfyWrapper(ofy.cache(value))
  def transaction(): Ofy = new OfyWrapper(ofy.transaction())
  def transactionless(): Ofy = new OfyWrapper(ofy.transactionless())
  def transact[O <: Objectify, R](work: TxnWork[O, R]): R = ofy.transact(work)
  def transact[O <: Objectify, R](limitTries: Int, work: TxnWork[O, R]): R = ofy.transact(limitTries, work)
  def clear = ofy.clear
  def setWrapper(ofy: Objectify) = ofy.setWrapper(ofy)
  def toEntity(pojo: Object): Entity = ofy.toEntity(pojo)
  def toPojo[T](entity: Entity) : T = ofy.toPojo(entity)
  
}

OfyWrapper.scala

class OfyWrapper(val base: Objectify) extends Ofy {
  
  base.setWrapper(this)
  
  override def ofy: Objectify = base
  
}

ScalaLoader.scala

class ScalaLoader(val loader: Loader) extends LoaderWrapper[ScalaLoader](loader) {
  
  def kind[E](kind: Class[E]): LoadType[E] = loader.`type`(kind)
  
}

User.scala

@Entity
case class User(
    @Id var email: String,
    @Index var password: String,
    var name: String,
    var company: Ref[Company]
  ) {
  
  // Only for Objectify creation
  private def this() { this(null, null, null, null) }
  
}

Code for http://thoughtsofthree.com/2012/04/scala-objectify4/