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

[Lindenmaier, Goetz]

Hi,

the subject should mention 8218628. (Not 8218626).
Sorry for this!

Best regards,
  Goetz.

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.