All Scala values are objects; there is no formal “primitive” type as there is in Java. However, there is a distinction in the main object tree.

Every object is a subtype of Any, however in practice, most objects will be a subtype of AnyRef. AnyVal is a superclass for the types that, in Java, are considered “primitive” (that being things like int, byte, and float). Further, all classes implicitly extend scala.ScalaObject (which is a Mixins(trait)).