+1. But adding this to the GCMXBean would mean changing that interface, and that gets into all sorts of versioning problems. Perhaps a better way would be to create a new GCMXBean interface (let's call it GarbageCollectorMXBean2 just for cruelty's sake) and offer it through the JMX server as well.
Ted Neward Java, .NET, XML Services Consulting, Teaching, Speaking, Writing http://www.tedneward.com > -----Original Message----- > From: [email protected] [mailto:jvm- > [EMAIL PROTECTED] On Behalf Of Attila Szegedi > Sent: Monday, January 14, 2008 12:42 AM > To: [email protected] > Subject: [jvm-l] Re: Ability to force class unloading in JDK 6 Update > 4? > > > Sounds like that's exactly what it does - includes a permgen sweep on > explicit System.gc() invocation. > > I have very mixed feelings about this. I mean, in a properly > implemented (ideal) JVM, why would you ever need this (or any other > explicit GC, for that matter)? > > OTOH, leaving ideal worlds aside, it can be a blessing if you'd ever > have a programmatic need to nudge (a real world, non-ideal) VM into > freeing up unused code. > > But still, the implementation bothers me. Applications shouldn't have > explicit System.gc() invocations, and even if I wanted to suggest the > JVM it'd be good time to do a permgen sweep, I think it's a bad idea > to overload System.gc() as the API for that purpose (and then > operationally rely on JVM being launched with this new command line > flag). Adding a method to either ClassLoadingMXBean or > GarbageCollectorMXBean in java.lang.management would've been a much > cleaner approach. > > Attila. > > On 2008.01.14., at 8:49, Charles Oliver Nutter wrote: > > > > > I stumbled across a blog post mentioning a new feature in an > > "experimental VM"...but perhaps it's now in JDK 6 Update 4? > > > > -XX:+ExplicitGCInvokesConcurrentAndUnloadsClasses > > > > Anyone know about it? > > > > http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6541037 > > > > I would expect that it doesn't change the fact that ClassLoader > > holds a > > hard reference to all classes it loads, but perhaps it helps force > > dereferenced classes in dereferenced classloaders to get collected > > more > > quickly? > > > > - Charlie > > > > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.516 / Virus Database: 269.19.2/1222 - Release Date: > 1/13/2008 12:23 PM > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.2/1222 - Release Date: 1/13/2008 12:23 PM --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "JVM Languages" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/jvm-languages?hl=en -~----------~----~----~----~------~----~------~--~---
