Re: Java Arrays.sort throws exception

From:

Owen Jacobson <angrybaldguy@gmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 15 May 2008 07:50:33 -0700 (PDT)

Message-ID:

<b3c43f09-82a0-4a37-95ff-11514c18e618@e39g2000hsf.googlegroups.com>

On May 15, 8:31 am, Lew <l...@lewscanon.com> wrote:

Philipp wrote:

Tom Anderson wrote:

On Wed, 14 May 2008, Owen Jacobson wrote:

On May 14, 10:37 am, captain <bdvolta...@yahoo.com> wrote:

When the number of elements gets above around 2700 the Arrays.sort
inside the Collections.sort throws an exception:

java.lang.ArrayIndexOutOfBoundsException

Any ideas?

Thanks

I've seen this happen when the Comparator (or Comparable)
implementation is not consistent.

My money is on some kind of bug in compareTo too. I don't see what
else it can be.

Could it be that the comparator must be consistent with equals for the
sort to work?

That would be Owen's point.

Not as such. My point was that identities like a < b && b < c is
implied by and implies that a < c, along with simpler ones like a < b
implies that b > a, must be implemented by the compareTo or compare
method in use. None of the sort implementations in the JRE bother
checking for .equals equality; they rely on .compareTo/.compare
equality.

-o