Janice J. Heiss of the Sun Developer Network interviewed Java Champion Kirk Pepperdine in a java.net Community Corner podcast recorded at JavaOne. Early in the interview, Janice asked Kirk about the nature of performance tuning. Kirk opens many of his presentations with the following statement (for example, see slide 4 in the presentation Kirk used in the Java Performance Tuning mini-talk he gave in the java.net booth at JavaOne):

The resemblance of any opinion, recommendation or comment made during this presentation to performance tuning advice is merely coincidental.

By this, he means that each performance tuning problem is unique. There is no such thing as one answer that fits all cases.

Kirk makes a distinction between developers and testers. Developers believe they know innately how to make an application faster. But often, what seems from a developer's point of view to be a way of coding that will result in better performance doesn't turn out that way. Meanwhile, someone whose job is to test software looks for bottlenecks in the code as it executes, rather than thinking in terms of the design and implementation of the code.

Kirk says that one of the greatest causes of poorly performing applications is overly complicated code. One of the reasons for this, in Java code, is that complex code can confuse the compiler, resulting in the code not being fully optimized. In this sense, sometimes writing 10 lines can produce a faster application than a clever 3-line implementation that accomplishes the same task. If the compiler doesn't "understand" the cleverness, it won't know how to optimize it; whereas the more straightforward 10 lines will be reduced into highly efficient byte code. Hence, the developer's fewer lines and characters can end up having poorer performance in the actual operational application.

Kirk sees cloud computing as not too different from the large data centers that we have today. The network issues are a potential complication. With respect to performance tuning in the cloud, Kirk says the difficulty is the lack of tools available for analyzing applications that run in the cloud.

Janice asked Kirk about JDK 7. He sees the added concurrency aspects as being the most important, along with improvements that will become available in developer tools.

In response to Janice's questions about JavaOne 2009 and the general mood of the conference, Kirk said people are concerned about the acquisition of Sun by Oracle. His view is that the other recent Java-related acquisitions by Oracle have generally turned out well. He thinks there are definitely some positive possibilities that might come out of the acquisition, especially with regard to addressing the issue of fragmentation of the Java platform.

The 26-minute podcast lets you see a different side of Kirk Pepperdine from what you see in one of his formal presentations (for example, the mini-talk podcast mentioned above). Janice has interviewed Kirk in the past, so their chat proceeds like it's part of a conversation that's been going on for years, and which (they and we hope) will continue at next year's JavaOne conference.

You can find all this year's java.net Community Corner podcasts as they are published on the JavaOne Community Corner Podcast page.