Hi David, Chris, On 11/10/2014 04:53 PM, Chris Hegarty wrote: > On 10/11/14 12:56, David Holmes wrote: >> On 10/11/2014 9:52 PM, Chris Hegarty wrote: >>> I have only looked at the libraries changes, and I think they make sense >>> . As in, I can find no reason why the name cannot be changed to be a >>> String. >> >> Very quick response, but IIRC this has been examined in the past and >> there were reasons why it can't/shouldn't be done. Will try to dig out >> more details in the morning. > > If there was previous discussion on this, that revealed some substantial > issue, that would be great, but I can't recall, or find, it now. > > Hotspot express, and the desire for hotspot to run with different > library versions, would certainly cause complication, but I don't > believe that is an issue now. > > Just on that, the library changes are minimal, and if this were to > proceed then they can accompany the hotspot change, as they make their > way into jdk9/dev. > > Anyway, this should await your reply.
Alan was having the same concern, there is an issue with JNI/JVMTI and other power users that might break when exposed to under-constructed Thread, e.g: https://bugs.openjdk.java.net/browse/JDK-6412693 This is why I ran jvmti and serviceability tests for this change, yielding no failures. This reinforces my belief this patch does not break the important invariant: if there is a problem with "Thread.name = name.toCharArray()" anywhere in Thread code, then "Thread.name = name" does neither regress it further nor fixes it. Then I speculated that having char[] name would help VM initialize the name if we wanted to switch to complete VM-side initialization of Thread, but it seems we can do String oop instantiation in the similar vein. Caching the name feels like a band-aid, that will probably complicate the Thread initialization on VM side even more. Let's wait and see if David can come up with some horror issue we are overlooking. :) Thanks, -Aleksey.
