RFR(L): 8218628: Add detailed message to NullPointerException describing what is null.

[coleen.phillimore at oracle.com]

On 5/7/19 9:36 AM, Lindenmaier, Goetz wrote:
> Hi,
>
> Please have a look at this further improved webrev:
> http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/09/
> http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/09-incremental/
>
> Harold, Coleen, thanks for pointing me to those methods.
> I'm using them now. This simplifies the helper methods
> considerably.
>
> Ralf, thanks for looking at the messages!
> I now suppress the "static " and
> "The return value of '" strings in the array subscript
> expressions and added corresponding test cases.
>
> About "can not" versus "cannot", what I find in the
> net "cannot" is to be preferred.  Any comments on that?
> By native speakers?
> See example messages here:
> http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/09/output_with_debug_info.txt

Cannot is apparently preferable in English.  Native speaker (only 
language) but somebody had to tell me.

Coleen
>
> Further, I fixed a build issue with the solaris compiler.
> All handling of bci is now unsigned.
>
> Best regards,
>    Goetz.
>
>
>
>
>> -----Original Message-----
>> From: Schmelter, Ralf
>> Sent: Dienstag, 7. Mai 2019 14:35
>> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; Java Core Libs <core-
>> libs-dev at openjdk.java.net>; hotspot-runtime-dev at openjdk.java.net; Coleen
>> Phillimore (coleen.phillimore at oracle.com) <coleen.phillimore at oracle.com>
>> Subject: RE: RFR(L): 8218628: Add detailed message to NullPointerException
>> describing what is null.
>>
>> Hi Goetz,
>>
>> I've played with the messages a little bit and they generally look good. But I've
>> come across two which look strange:
>>   - 'o[static Test.INDEX]' is null. Can not invoke method 'int
>> java.lang.Object.hashCode()'
>>   - 'o[The return value of 'int java.lang.String.hashCode()]' is null. Can not invoke
>> method 'int java.lang.Object.hashCode()'.
>>
>> Here is the test program to reproduce these:
>> public class Test {
>>      public static int INDEX = 2;
>>
>>      public static void main(String[] args) {
>>          Object[] o = new Object[10];
>>          try {
>>               o[INDEX].hashCode();
>>          } catch (Exception e) {
>>              e.printStackTrace();
>>          }
>>          try {
>>               o["".hashCode()].hashCode();
>>          } catch (Exception e) {
>>              e.printStackTrace();
>>          }
>>      }
>> }
>>
>> And 'Can not' should be 'Cannot'?
>>
>> Best regards,
>> Ralf