java.util.Calendar.clone() hasn't been updated for 5.0

java.util.Calendar.clone() returns Object. What?!?!?!? Are you crazy? This function overrides Object.clone(), so there's no need to use an Object return type. The return type will *always* be Calendar. And, Java 5.0 specifically allows for this (return type to be a subclass of overridden method's return type). In "Java in a Nutshell", David Flanagan notes (pg. 120, 5th ed.):

In Java 5.0 and later, the return type of the overriding method may be a subclass of return type of the overridden method instead of being exactly the same return type. This is known as a covariant return and is described in "Covariant Return Types" in Chapter 2.

Hopefully the Object return type is an oversight that will be corrected in Java 6.