Re: What methods should go into a java.util.Objects class in JDK 7?

[Joe Darcy]

On 09/09/09 08:01 PM, Joe Darcy wrote:
Martin Buchholz wrote:
On Wed, Sep 9, 2009 at 17:40, Joe Darcy<joe.da...@sun.com> wrote:
 
PS This talk of hashing remind me of a small spec cleanup:
4245470 algorithm of java.lang.Byte.hashCode() is not specified
http://bugs.sun.com/view_bug.do?bug_id=4245470
    

http://cr.openjdk.java.net/~martin/webrevs/openjdk7/hashCode-spec/

Martin
  

I'll work on the archeology to verify this behavior has been 
consistent over time and thus is reasonable to tighten the spec in 
these cases.

-Joe

Martin,

I noticed that the Character class should be similarly tightened:

    /**
    * Returns a hash code for this {...@code Character}; equal to the result
    * of invoking {...@code intValue()}.
    *
    * @return a hash code value for this {...@code Character}
    */
   public int hashCode()

I've done some checking and all of the following Sun JDKs implement the 
"intValue" hashCode for Byte, Character, and Short:

1.1
1.2
1.3.0
1.3.1
1,4.0
1.4.1
1.4.2
1.5
1.6

so I think a change to all three wrapper classes is safe to go back from 
a behavioral compatibility perspective :-)

-Joe