Scala Cookbook

17.3. Using @SerialVersionUID and Other Annotations

Problem

You want to specify that a class is serializable, and set the serialVersionUID. More generally, you want to know the syntax for using annotations in your Scala code, and know which annotations are available.

Solution

Use the Scala @SerialVersionUID annotation while also having your class extend the Serializable trait:

@SerialVersionUID(1000L)
class Foo extends Serializable {
  // class code here
}

Note that Scala has a serializable annotation, but it has been deprecated since version 2.9.0. The serializable annotation Scaladoc includes the following note:

instead of @serializable class C, use class C extends Serializable

Discussion

In addition to the @SerialVersionUID annotation and the Serializable trait, Scala has other annotations that should be used for various purposes, including the cloneable, remote, transient, and volatile annotations. Based primarily on the “A Tour of Scala Annotations” web page, Table 17-3 shows a mapping of Scala annotations to their Java equivalents.

Table 17-3. Scala annotations and their Java equivalents

Scala	Java
scala.beans.BeanProperty	No equivalent. When added to a class field, it results in getter and setter methods being generated that match the JavaBean specification.
scala.cloneable	java.lang.Cloneable
scala.deprecated	java.lang.Deprecated
scala.inline	Per the Scaladoc, @inline “requests that the compiler should try especially hard to inline the annotated method.”
scala.native	The Java native keyword.