Name: skT45625 Date: 05/08/2000


java version "1.3.0rc3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0rc3-Z)
Java HotSpot(TM) Client VM (build 1.3.0rc3-Z, mixed mode)


I am trying to compile a class. At the beginning I have:

public class DSForest implements Serializable {
  private Set reps;



Later on I have:

  public Set getRepresentatives () {
    return reps.clone();
  }

(Yes, it looks like this is exposing an implementation detail, but this class
is for a specialized purpose in a project, and is not meant for re-use. A
generic disjoint set forest won't do here.)

The weirdest message results at compile time:

src\pgd\companion\util\DSForest.java:91: clone() has protected access in
java.lang.Object
    return reps.clone();

This looks like a bug to me, perhaps a compiler bug, perhaps a bug in Object,
and perhaps a bug with the Set.

I used a HashSet for the Set; this is documented to be cloneable. In any case,
what I expect to get when I take any Object and clone it is either a clone or a
CloneNotSupportedException at runtime, never a compile time error. JDK 1.3 RC3
seems to have broken something.

Inspecting Object.clone() in the docs, it is indeed "protected" now, which is
peculiar, but this access specifier should act exactly like "public" on an
Object method, because every reference type is descended from Object! In
particular, DSForest is an Object, so can call clone() on any Object, including
the Set; this should be dispatched polymorphically to call HashSet's clone();
since HashSet is Cloneable this should work perfectly, without even throwing a
CloneNotSupported exception at runtime.
(Review ID: 104537)
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