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I have a problem on Scala. I serialize an instance of class with @transient lazy val field. And then I deserialize it, the field is assigned null . I expect the lazy evaluation after deserialization. What should I do? Following is a sample code. object Test { def main(args: Array[String]){ //---------------- // ClassA - with @transient //---------------- val objA1 = ClassA("world"); println(objA1); // This works as expected as follows: // "Good morning." // "Hello, world" saveObject("testA.dat", objA1); val objA2 = loadObject("testA.dat").asInstanceOf[ClassA]; println(objA2); // I expect this will work as follows: // "Good morning." // "Hello, world" // but actually it works as follows: // "null" //---------------- // ClassB - without @transient // this works as expected //---------------- val objB1 = ClassB("world"); println(objB1); // This works as expected as follows: // "Good morning." // "Hello, world" saveObject("testB.dat", objB1); val objB2 = loadObject("testB.dat").asInstanceOf[ClassB]; println(objB2); // This works as expected as follows: // "Hello, world" } case class ClassA(name: String){ @transient private lazy val msg = { println("Good morning."); "Hello, " + name; } override def toString = msg; } case class ClassB(name: String){ private lazy val msg = { println("Good morning."); "Hello, " + name; } override def toString = msg; } import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; def saveObject(fname: String, obj: AnyRef){ val fop = new FileOutputStream(fname); val oop = new ObjectOutputStream(fop); try { oop.writeObject(obj); } finally { oop.close(); } }

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