pf » Tag: jvm on Pete Freitag's Blog

Bea has released JRockit 5.0 JVM. Here is a link to some release notes.

JRockit 5.0 is a J2SE 5.0 compatible Java Runtime Environment. The JRockit JVM main design goal is performance, and the 5.0 version shows a 5-10% performance increase over their previous version on linux.

The first patchset for Java 1.5 on FreeBSD has been released.

Greg Lewis has released the first patchset (patchlevel 1) for the JDK" 1.5.0 software. This is initial patchset and suitable for early testers and developers.

I found myself today needing to deal with unsigned integers, and shorts in java. In Java there is no unsigned keyword like in C, or other languages. All primitives are signed (meaning they can hold negative values).

Robi Sen a while back posted a blog entry with some useful tips on solving java.lang.OutOfMemory exceptions, and tuning the JVM for ColdFusion MX. He has recently posted a follow up to that entry.

Last week I wrote a Server Memory monitoring tool using Flash Remoting. I'm not much of a flash developer, but it only took a few hours. Here's a screen shot of the tool:

Keep in mind this tool only shows the memory for the JVM instance that ColdFusion MX is running in.

Sun has released (for free) a very cool program called Visual GC 2.0 in their jvmstat toolkit (via: Moazam Raja). The tool will show you graphically how memory is organized into generation in your JVM.

Macromedia's Recent Technote: Maximum JVM heap size greater than 1.8GB will prevent ColdFusion MX from starting points out the limitations of a the JVM on a 32 bit architecture.

Wondering where the number 1.8GB comes from? Moazam Raja's recent blog entry explains.

Now that you have had a chance to read my outline of garbage collection tuning in java. You should be asking yourself how does this relate to my ColdFusion server. Or maybe you just wondered what Garbage Collection has to do with ColdFusion Servers.

Every so often I come across the document: Tuning Garbage Collection, and I attempt to read all of it. The document is kind of hard to digest, so this time I created an outline of the Tuning Garbage Collection on the Java 1.4.2 Hotspot JVM document.

Here are some code to find out some info about the memory usage of CFMX or BlueDragon. The Java API provides three methods in the java.lang.Runtime class: freeMemory, totalMemory, and maxMemory.

I recently had to reinstall my OS, and more recently had to use a Java Application called JEdit. JEdit's installer didn't create any shortcuts for me, so I had to run JEdit from the command line by invoking it's jar file with java -jar jEdit.jar.

ColdFusion's move to java gives developers and system administrators a wealth of performance tuning options.