Hi Goetz, thanks for bringing this into OpenJDK finally. I know of people that'll be quite happy about this feature.
I had a quick glance through the code. Here are a few findings: src/java.base/share/classes/java/lang/NullPointerException.java: line 56: remove a space before the comment line 62: private transient boolean lazyComputeDefaultMessage; I think the name for this variable is not well chosen. I'd prefer lazyComputeMessage, because it's not a default message, it's rather "the" message of the exception. Then, I think you should initialize the field right away in this line to true, no need to do it in the constructor. (Or can't that be done for transient fields?? 😊) 122 private native void setDefaultMessage(String extendedMessage); Here, I agree with David, that you should do it in Java. Just use a shared secret, then you don't even need reflection... It also should not be "setDefaultMessage" but rather "setMessage". Best regards Christoph > -----Original Message----- > From: hotspot-runtime-dev <hotspot-runtime-dev- > boun...@openjdk.java.net> On Behalf Of Lindenmaier, Goetz > Sent: Donnerstag, 7. Februar 2019 17:43 > To: hotspot-runtime-...@openjdk.java.net; Java Core Libs <core-libs- > d...@openjdk.java.net> > Subject: [CAUTION] RFR(L): 8218628: Add detailed message to > NullPointerException describing what is null. > > Hi, > > since Java 5, our internal VM reports verbose null pointer exception > messages. I would like to contribute this feature to OpenJDK. > > With this change, messages as > "java.lang.NullPointerException: while trying to load from a null int array > loaded from local variable 'ia1'" > are printed. For more examples see the JBS bug or the test included. > https://bugs.openjdk.java.net/browse/JDK-8218628 > > The messages are generated by parsing the bytecodes. For not to have any > overhead when the > NPE is allocated, the message is only generated when it is accessed by > getMessage() or > serialization. For this I added a field to NPE to indicate that the message > still > needs to be > computed lazily. > > Please review: > http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/01/ > I'm happy to incorporate your comments. > > Best regards, > Goetz >
