[OpenJDK 2D-Dev] Review Request for JDK-8153943 : In java.awt.image package some of the classes are missing hashCode() or equals() method

[Jim Graham]

This is actually a pretty nasty issue that Joe Darcy also brought up in 
the CCC review.

In order to have symmetric testing of .equals(), we pretty much have to 
enforce this test at all levels, including in the original 
ColorModels.equals() method.  If we don't enforce this in CM.equals(), 
then we could run ccm.equals(othercm) and it would return false because 
the class is wrong, but turning it around and testing 
othercm.equals(ccm) would succeed because it doesn't enforce the class 
equality.

So, I'd recommend that CM.equals() tests getClass() == getClass() at the 
base level and then all others will use super.equals() and get the same 
protection.  It means you can't have a subclass of CCM be "equals" to a 
different subclass of CCM, but that's an unfortunate issue with equals 
needing to honor symmetry...  :(

			...jim

On 4/20/2016 10:17 AM, Phil Race wrote:
> Hi, You removed the following test in CCM.java : 2941 if (obj.getClass()
> != getClass()) {
> 2942 return false;
>
> 2943         }
>
> What this means is that before your change an instance of a subclass of CCM
> would never be equals() to any direct instantiatation of CCM but after
> your change it can be. I suspect the condition was there on purpose.
>
> -phil.
>
> On 04/20/2016 05:45 AM, Jayathirth D V wrote:
>>
>> Hi,
>>
>>
>>
>> _Please review the following fix in JDK9:_
>>
>>
>>
>> Bug : https://bugs.openjdk.java.net/browse/JDK-8153943
>>
>>
>>
>> This is subtask of https://bugs.openjdk.java.net/browse/JDK-6588409
>>
>>
>>
>> Webrev : http://cr.openjdk.java.net/~jdv/8153943/webrev.00/
>> <http://cr.openjdk.java.net/%7Ejdv/8153943/webrev.00/>
>>
>>
>>
>> Issue : Some of the java.awt.image classes are missing either equals()
>> or hashCode() method.
>>
>>
>>
>> Solution : Add missing equals() or hashCode() methods.
>>
>>
>>
>> Thanks,
>>
>> Jay
>>
>>
>>
>