Standing in the Field @ Valley Forge

Standing in the Field

Notes from SJS Application Server Field Engineering

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Wednesday April 20, 2005
DTrace and Java

Severalpeople have blogged this new java.net project that is a DTrace agent for Java. Since I've talked about DTrace and Java previously I figured that I should throw in my two cents. (Especially since I've been less than diligent in posting recently.) This project is very interesting and I'm hoping that it will be available as part of the standard JDK in the future. Most interestly, it has several probes that are going to allow DTrace to instrument method calls and GC events.

But it's important for me to note that you can already use DTrace to probe Java applications. Most notably jstack() does a reasonably good job of translating stacks into Java method names. Don't assume that you need this module to use DTrace effectively on a Java application. The new module does allow you to be more proactive and has some very useful trace points for doing active troubleshooting, but don't discount the out of the box DTrace functionality.

Also, the downside of this module is that it has to be actively installed into the JVM. Which takes away one of the advantages of DTrace: the fact that it is pre-integrated into the OS.

It is great to see this module. And it's especially great to see this as a java.net project with CDDL licensed source code. But it's probably best to just see this as a technology preview for what we will see as far as DTrace integration in Mustang.

(2005-04-20 11:18:57.0) Permalink