Re: [Japi] Abstract enums

[Stuart Ballard]

On 11/28/06, Jeroen Frijters <address@hidden> wrote:
> Where are you seeing this? I can't reproduce this with the versions of
> javac and ecj I have installed (both mark the class as abstract).

Well, according to Japize, TimeUnit is not abstract in JDK1.5. I was
assuming that JDK1.5 was using the same JSR166 sources that Classpath
is, but perhaps that's not the case. In fact now that you mentioned
this I looked at the jdk6 results and it does appear that TimeUnit
*is* abstract in jdk6. So presumably the sources Classpath is using
are newer than 1.5. Sorry for the confusion.

> Agreed. BTW, doesn't this also mean that you should ignore "abstract" on
> methods in an enum? After all, aren't these two enums the same:

Yes, good point. And (as would generally be the case for a final
class) treat all methods as final too.

> As an interesting aside, the VM does not actually prevent you from
> subclassing an enum with a regular class. This means that coupled with
> the "finalizer attack" you can actually create illegal enum values. This
> was fixed in 1.6 by adding a final finalize method to java.lang.Enum.

You mean that an enum has a non-private constructor? Why?

Or am I misunderstanding the "finalizer attack" and it doesn't
actually require one?

Stuart.
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