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Jack Shirazi

Jack Shirazi has been a Java Champion ( since 2005; is the founder of, the world's premier site for Java performance information; is the owner of; is the author of O'Reilly's "Java Performance Tuning"; and is senior Java developer at At, Jack has published several thousand performance tips as well as many articles about performance tools, discussion groups, and much more. Jack has also published work on protein structure prediction and black hole thermodynamics, and contributed to some Perl5 core modules.


jacksjpt's blog

Java at London techhub's most successful startup

Posted by jacksjpt on March 16, 2015 at 1:56 AM PDT

I thought some of you might be interested in hearing about Java and the Java dev team at a startup that's grown beyond the initial stage.

Google's Big Question: What's Different Now?

Posted by jacksjpt on November 13, 2014 at 9:00 AM PST

In Eric Schmidt's presentation "How Google Works", he asks and answers the question "What's Different Now?" for businesses in the 21st century. And the answers he gives are:

1. Cloud computing puts a supercomputer in your pocket.
2. Mobile devices mean anyone can reach anyone, anywhere, anytime.

Finding the right Java "sizeof" was one of my first tasks at Nexmo

Posted by jacksjpt on October 7, 2014 at 6:25 AM PDT

There are occasions when you need to know how much space a particular data structure is taking. You may have seen my recent newsletter about Java "sizeof" implementations which allow you to do that.

Java Support! Well done, Sun ARE responding

Posted by jacksjpt on January 3, 2007 at 5:04 AM PST

blogged a couple of years ago that Sun just didn't understand what their customers want, with the specific example of looking for Java support that I was expecting to pay for.

Well, now that support is available at

An incredibly useful JVM change suggestion

Posted by jacksjpt on May 25, 2005 at 4:36 AM PDT

I spend half my time trying to identify what performance systems are doing by reproducing their behaviour in a performance testbed.

Sun - don't you WANT to make money?

Posted by jacksjpt on April 8, 2005 at 6:22 AM PDT

I was looking for Sun Java support - paid support, not the freebie "stick your bug in the db, vote for it and if enough people vote we might do something about it" support. I was looking for something serious - "I pay you, you fix the damn problem or tell me a valid workaround that you support" type of support.

Java and coolness, a discussion

Posted by jacksjpt on September 22, 2004 at 1:04 PM PDT

In my last newsletter, I laid into those who criticise Java for what I see as simple jealousy. That lead to the following discussion with one of my readers, who I call "B" (I'm the "J" correspondent in the following discussion).

B. I've been a J2EE programmer for 3 years now, and a Java programmer for 6.

Java IDE comparison

Posted by jacksjpt on August 27, 2004 at 2:48 AM PDT

There is a "Java IDE shootout" from JavaOne 2004 at here (the pdf is available free and fairly detailed).

Integrating HTML validation to my site building process

Posted by jacksjpt on July 14, 2004 at 4:46 AM PDT

I generate my website using a local servlet container and JSP pages converting text source to html pages, then I upload all the pages to the server. Inspired by reading
Cleaning Your Web Pages with HTML Tidy, I decided it was about time I had my HTML validated.