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

[Lindenmaier, Goetz]

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

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