Code review request for 6891113: More methods for java.util.Objects: deepEquals, hash, toString with default

Joseph D. Darcy Joe.Darcy at Sun.COM
Fri Oct 23 18:23:09 UTC 2009

Joe Darcy wrote:
> Neal Gafter wrote:
>> There should be a shortcut in Arrays.deepEquals0 when e1==e2.  
> That shortcut is in Objects.deepEquals(Object a, Object b) and 
> Arrays.deepEquals on lines 3947 and 3948.  The nested call in 
> deepEquals0 is to deepEquals rather than deepEquals0 so the shortcut 
> is used on all levels.
>> Also, the code will throw an assertion error if e1!=null and e2==null 
>> (which can occur when called from Arrays.deepEquals).
> Good catch!  Yes, my mistake; only e1 != null is guaranteed when being 
> called from Arrays.deepEquals.
>> The simplest way to fix these is to move the if statements from 
>> Objects.deepEquals into Arrays.deepEquals0.  Alternately, change the 
>> call of Arrays.deepEquals0 in Arrays.deepEquals to a call to 
>> Objects.deepEquals.  If you do the latter, you might as well move all 
>> the code of deepEquals0 into the body of Object.deepEquals.
> For correctness, I think removing the assertion that e2 != null in 
> deepEquals0 is sufficient.
> Thanks,
> -Joe

The code with both asserts failed the Arrays regression tests with when 
run with system assertions enabled.  When the second assertion was 
removed, the tests passed with system assertions enabled and I've push 
that version.



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