Two years ago I have published cheat sheet for garbage collection options in HotSpot JVM.
Recently I decided give that work some refreshing and today I'm publishing first HostSpot JVM options ref card covering generic GC options and CMS tuning. (G1 have got a plenty of tuning options during last (more...)
Today was speaking at HighLoad++ 2013 Moscow. I had two presentation covering deep internals of JVM. One about JIT compilation and other concerning pauseless garbage collection algorithms.
Slide decks are below (in Russian)
I got into more coding again lately and that is a good thing I think. I’m a believer of the German saying “Wer rastet, der rostet” or in English: A rolling stone gathers no moss! Java seems to be my main programming language since quite a while now. But believe (more...)
Java 7u51 is scheduled for release in January. It will have some consequences for you Forms installation that you need to address.
As far as I know there is no problems with using 7u51 on the server side, only on the client side.
7u51 requires you to sign all RIAs (Applets and Web Start applications).
Oracle already signs the standard jar (more...)
- Entropy pool
- Monitoring entropy
- Using /dev/urandom
- JRE – java.security
- rngd daemon
- Additional information
In computing you often need random numbers. They are used for encrypting stuff but also for lots of other things.
SJK is small command line tool implementing number of helpful commands for JMV troubleshooting. Internally SJK is using same diagnostic APIs as standard JDK tools (e.g. jps, jstack, jmap, jconsole).
Recently I've made few noteworthy additions to SJK package and would like to announce them here.
Memory allocation rates (more...)
Oracle no longer posts updates of Java SE 6 and JRockit to its public download sites.
If you have a support contract you can download new updates from MOS.
You can locate the Java SE 6 downloads in this note “All Java SE Downloads on MOS (Doc ID 1439822.1)”.
Compressed OOPs (OOP – ordinary object pointer) is a technique reducing size of Java object in 64 bit environments. HotSpot wiki has a good article explaining details. Downside of this technique is what address uncompressing is required before accessing memory referenced by compressed OOPs. Instruction set (e.g. x86) may (more...)
This is a first articles in series, where I would like to study effect of various HotSpot JVM options on duration of STW pauses associated with garbage collection.
This article will study how number of parallel threads affects duration of young collection Stop-the-World pause. HotSpot JVM has several young GC (more...)
There are bunch of graphical tools helping you to look inside of running JVM (VisualVm and JConsole are extremely helpful). Unfortunately, some times (almost always in my case), you may find yourself in SSH console on headless server side by side with your JVM (more...)
On Linux low entropy can cause certain operations to be very slow.
SSL operations need entropy to ensure randomness. Entropy is generated by the OS when you use the keyboard, the mouse or the disk.
If an SSL operation is missing entropy it will wait until enough is generated.
Autocomplete was not working for JSF tags in my Eclipse. I googled it and finally found the solution on http://www.mkyong.com/jsf2/how-to-make-eclipse-ide-supports-jsf-2-0/
The different thing I did is; I downloaded javax.faces-2.xx.xx.jar and saved in a specific folder. Then I created a user library with this jar. I did not use “jsf-api-xxx.jar and jsf-impl-xxx.jar“.
First you have the java interface way which I described here (more...)