RFR [lworld] 8239929: Object.newIdentity() replacement for new Object()

[Mandy Chung]

Maybe suppress the warning from java.base in the build for the time 
being.  Any other module using new Object()?

Mandy

On 2/27/20 6:06 PM, Roger Riggs wrote:
> Hi Mandy,
>
> I don't think we are ready for the storm of compiler warnings.
> There are 100 in java.base alone.  We can change that later when we 
> are ready to phase it in.
>
> Roger
>
>
> On 2/27/20 5:40 PM, Mandy Chung wrote:
>> I think we should add @Deprecated in the Object constructor.
>>
>> Otherwise, looks fine.
>>
>> Mandy
>>
>> On 2/25/20 11:20 AM, Roger Riggs wrote:
>>> Please review the static factory of an IdentityObject to replace 
>>> "new Object()"
>>> as mentioned in [1].
>>>
>>> No replacements proposed yet.  There are 504 instances of "new 
>>> Object()" in JDK modules.
>>> @@ -38,15 +38,36 @@
>>>
>>>   */
>>>  public class Object {
>>>
>>>      /**
>>>       * Constructs a new object.
>>> +     * @apiNote {@link Object#newIdentity} should be used instead 
>>> of {@code new Object()}.
>>>       */
>>>      @HotSpotIntrinsicCandidate
>>>      public Object() {}
>>>
>>>      /**
>>> +     * Constructs a new Object implementing the IdentityObject 
>>> interface.
>>> +     * The object is a unique IdentityObject suitable for all purposes
>>> +     * that previously for which {@code new Object{}} was used 
>>> including synchronization,
>>> +     * mutexes and unique placeholders.
>>> +     *
>>> +     * @return a new Object implementing the IdentityObject interface
>>> +     * @since Valhalla
>>> +     */
>>> +    public static IdentityObject newIdentity() {
>>> +        return new IdentityInstance();
>>> +    }
>>> +
>>> +    /**
>>> +     * IdentityInstance replaces plain {@code new Object()}.
>>> +     */
>>> +    private final static class IdentityInstance implements 
>>> IdentityObject {
>>> +        private IdentityInstance() {}
>>> +    }
>>> +
>>>
>>>
>>> As a Webrev:
>>> http://cr.openjdk.java.net/~rriggs/webrev-object-newinstance-8239929/
>>>
>>> Thanks, Roger
>>>
>>> [1] 
>>> http://cr.openjdk.java.net/~briangoetz/valhalla/sov/02-object-model.html 
>>>
>>
>