Slides for the JavaOne 2009 tech sessions
Hi all,
The slides for the JavaOne 2009 tech sessions have been posted here. Here are my two sessions, if you missed them:
Thursday: Garbage Collection Tuning in the Java HotSpot Virtual Machine (with Charlie Hunt) link
Friday: Inside Out: A Modern Virtual Machine Revealed (with John Coomes and Brian Goetz) link
If you were there, thanks for coming to listen to us! Let me know if you liked the talks.
Tony
Posted at 09:27AM Jun 12, 2009 by tony in Personal | Comments[3]
JDK 6u10 / HotSpot 11 are now released
JDK 6 update 10 has just been released. You can find more information about it here and you can download it from here.
JDK 6u10 is the first JDK to be released with HotSpot 11 (the four previous ones, 6u4, 6u5, 6u6, and 6u7, all had HotSpot 10). The main changes that went into HotSpot 11 were some nice performance improvements (especially in the server compiler front) and, as always, some bug fixes.
For the OpenJDK geeks out there, HotSpot 11 also has the distinction of being the final HotSpot release to be managed by Teamware. After that, we moved to Mercurial.
Enjoy.
Posted at 11:12AM Oct 27, 2008 by tony in Sun | Comments[4]
Real-Time Java Tutorial at OOPSLA 2008
Will anyone be going to OOPSLA in Nashville next month? David Holmes and I will be repeating our "Real-Time Programming on the Java Platform" tutorial that was quite popular at last year's OOPSLA. It's tutorial 28 and it will take place on Monday, Oct 20, 2008 in the afternoon (at least we got a better time slot this year!). David will cover a lot of the main concepts behind the RTSJ (Real-Time Specification for Java) and I will cover a lot of the issues concerning real-time garbage collection.
Hope to see you there (either at the tutorial or at OOPSLA in general).
Posted at 09:16AM Sep 22, 2008 by tony in Sun | Comments[2]
I told you finalizers are bad for you!
Hi all,
Read this interesting thread on forums.sun.com. The quick description is the following. The poster's application kept hitting an OutOfMemory situtation after a few hours of running. A little investigation showed that most of the memory in the heap (850+MB out of a 1.2GB heap) was being held by, you guessed it!, the finalization queue. The reason? A finalizer was getting stuck on I/O (while closing a DB connection) and preventing the rest from running, while more and more objects were added to the queue. Ouch.
The poster advises: Never do I/O in a finalizer! I actually advise: Never use finalizers in the first place!
But, if you really really have to, you should be really really really careful.
Posted at 10:25AM Aug 12, 2008 by tony in Personal | Comments[2]
The Saddest News (cont'd)
Just a quick follow-up on Steve Goldman's passing. His obituary was published here, if you're interested in reading it.
BTW, I just realized: I've been using Xinha to write my blog entries... and guess who had introduced me to it? Yep, Steve.
Posted at 05:01PM Jul 08, 2008 by tony in Sun | Comments[0]
Sun Rays
I've always been mystified why Sun Rays (Sun's thin clients) have not been more popular. They might not be a generic desktop replacement, but they are definitely the right solution in many situations, e.g., call centers. Nice to see that someone else thinks so too.
Posted at 12:35PM Jul 07, 2008 by tony in Sun | Comments[4]
The Saddest News
Not all blogs entries are pleasant or easy to write.
Today we got the saddest news. One of our own, Steve Goldman, passed away while on vacation. He was 56. He is survived by his wife, Gretchen Niver, and their two nieces.
Steve has been working on Java and HotSpot since 1999. He was initially part of the runtime team and then moved to the compiler team. His contributions to HotSpot are too many to enumerate. HotSpot would just not be what it is if Steve had not worked on it. You can read his blog here.
Steve and I shared a hobby: aviation. He was an avid pilot and for the past two years he has been building his own Velocity. Here he is, in his partially-constructed Velocity, after he installed the control stick.
As another colleague today said, Steve's passing is a huge loss to Sun and the world. I could not agree more.
Steve, we will miss you. In fact, we miss you already. Wherever you are, may the winds be calm and the skies clear.
Godspeed.
Posted at 01:01PM Jun 30, 2008 by tony in Sun | Comments[3]
Join the OpenJDK HotSpot GC lists!
Hi all,
(alright, yes, I really needed to get back to blogging!)
We recently wanted to get feedback on a couple of changes that we are planning to the GC-related command line parameters of HotSpot. And we opened the discussion on the OpenJDK HotSpot GC mailing lists. So, I'd like to take this opportunity to encourage you to join those lists, if you're interested in participating in such discussions. We maintain two lists:
hotspot-gc-use (for discussion on the use of our GCs):
http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use
hotspot-gc-dev (for discussions on the code of our GCs):
http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-dev
(Note that the latter is a member of the former. So, you don't have to become a member of both.)
And, for what it is worth, the questions we have been asking are the following:
http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2008-April/000237.html
http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2008-May/000309.html
Posted at 11:53AM May 30, 2008 by tony in Sun | Comments[2]
"Did I mention it was free?"
Very interesting article on Scott McNealy's presentation at the NICSA Technology Summit 2007 in Las Vegas on the advantages of open source software. Worth a read if you're not yet convinced.
Posted at 01:05PM Oct 29, 2007 by tony in Sun | Comments[1]
The T2 is finally out!
The first systems, the Sun SPARC Enterprise T5120 and T5220 servers and the Sun Blade T6320, which are based on our new UltraSPARC T2 (aka Niagara 2) chip have finally been announced. Congratulations to all the teams involved!
Compared to the T1, T2 has several nice improvements. I'll only concentrate on two: 8, instead of 4, hardware threads per core (for an incredible total of 64 hardware threads per chip) and 1 FPU per core, instead of 1 FPU per chip (for a total of 8 FPUs per chip). This will give you even more parallelism, as well as much better FPU performance, compared to the T1.
Please check this blog entry for an overview of all the benefits of the UltraSPARC T2.
We, the HotSpot JVM development team, have been doing a lot of work to make sure that HotSpot runs as well as possible on the T2. And it shows. Check out the SPECjbb2005 results that we have published on Dave Dagastine's blog. We were particularly happy with the single JVM result that we got on T2, which is just over 10% worse than our best multiple JVM result.
Posted at 05:02PM Oct 09, 2007 by tony in Sun | Comments[0]
Solaris: "Signs of Life"
Check out this article on Solaris getting traction. Pretty cool.
Posted at 11:55AM Oct 08, 2007 by tony in Sun | Comments[0]
Finalization article, version 2.0
The finalization article that I had written sometime ago, has been revamped and republished on java.sun.com:
http://java.sun.com/developer/technicalArticles/javase/finalization/
Posted at 06:30AM Sep 17, 2007 by tony in Sun | Comments[0]
Write Dumb Code
"Often, the way to write fast code in Java applications is to write dumb code --- code that is straightforward, clean, and follows the most obvious object-oriented principles."
Who said it? Well, you need to go here to find out.
Posted at 09:44AM Mar 05, 2007 by tony in Sun | Comments[1]
Nice article on the Java Real-Time System
First, Happy New Year! I hope you all had a great and relaxing break!
For the past several months I've actually been doing some work on Java RTS (Java Real-Time System). Eric Bruno just published a nice introductory article on it. So, if you want to know more about Java RTS, I'd encourage you to go and have a look. Can you find the article here here.
Posted at 08:54AM Jan 08, 2007 by tony in Sun | Comments[1]
Nice performance improvement with Java SE 6!
Hey, check out this post:
http://forum.java.sun.com/thread.jspa?forumID=37&threadID=5114368
30% performance improvement by just switching from 5.0 to 6.0. Pretty Cool! As I said in my previous post: What are you waiting for? Go and get it. Now!
Posted at 09:43PM Dec 11, 2006 by tony in Sun | Comments[0]