RFR (L, final): 8218626: Add detailed message to NullPointerException describing what is null.

[Roger Riggs]

Hi Goetz,

A bit of wordsmithing on the javadoc of NullPointerException.getMessage
and separating out the implementation specific description to an @implNote

75:
     /**
      * Returns the detail message string of this throwable.
      * <p>
      * If a non-null message was supplied in a constructor it is returned.
      * Otherwise, an implementation specific message or {@code null} is returned.
      * @ImplNote
      * If no explicit message was passed to the constructor, and as
      * long as certain internal information is available, a verbose
      * description of the null reference is returned.
      * The internal information is not available in deserialized NullPointerExceptions.
      *
      * @return the detail message string, which may be {@code null}.
      *

94-97: The comment on the getExtendedNPEMessage should use the normal 
/**... */ syntax.

Thanks, Roger



On 9/17/19 10:18 AM, Lindenmaier, Goetz wrote:
> @core-libs experts, I would appreciate comments on the changes
> to NullPointerException.java, especially wrt. the Javadoc comment.
> The change there is S.
>
> Best regards,
>    Goetz.
>
>> -----Original Message-----
>> From: Lindenmaier, Goetz
>> Sent: Dienstag, 10. September 2019 11:48
>> To: 'Hotspot dev runtime' <hotspot-runtime-dev at openjdk.java.net>; Java Core
>> Libs <core-libs-dev at openjdk.java.net>
>> Subject: RFR (L, final): 8218626: Add detailed message to NullPointerException
>> describing what is null.
>>
>> Hi,
>>
>>
>>
>> this is the implementation of JEP 358: Helpful NullPointerExceptions.
>>
>>
>>
>> The JEP is in status "Candidate". Coleen (many, many thanks!) ran
>>
>> it through the Oracle-internal processes.  Now I please need final reviews
>>
>> for this change so that I can propose it to target jdk 14.
>>
>>
>>
>> JEP: https://bugs.openjdk.java.net/browse/JDK-8220715
>>
>> Enhancement: https://bugs.openjdk.java.net/browse/JDK-8218628
>>
>> webrev: http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/16/
>>
>>
>>
>> The change ran through a lot of testing, all jtreg and jck tests to name
>>
>> only some. The webrev points to patch
>>
>> http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-
>> NPE/16/enable_NPE_message.patch
>>
>> that enables the change by default,  which was useful for testing to
>>
>> assure the code is used in the tests.
>>
>> I just pushed the change to jdk/submit once more.
>>
>>
>>
>> Please review.
>>
>>
>>
>> Thanks!
>>
>>    Goetz.