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Santiago Pericas-Geertsen

Santiago holds a PhD in computer science from Boston University, where he specialized in programming languages and compilers. He has been a staff engineer at Sun/Oracle for 9 years. In his first project, he co-developed XSLTC: an XSLT to bytecode compiler now in the JDK. In the next few years his focus was on XML performance and binary XML and developed the Japex micro-benchmark framework. He participated, and was appointed editor, in a number of initiatives in this area including the W3C XML Binary Characterization WG and the W3C Efficient XML Interchange WG. Before joining the Glassfish Web Tier team at Oracle, he was tech lead for JAXP and also worked on the Glassfish Mobility Platform. Currently, he is the co-spec lead for JAX-RS 2.0 (JSR 339).


spericas's blog

SJSXP 1.0.1 available from

Posted by spericas on February 20, 2007 at 9:01 AM PST

The Sun Java Streaming XML Parser (SJSXP) 1.0.1 is now available for download from This is our first release since FCS back in April 2006. In his new blog, Joe Wang has already talked about this new release as well as some of the fixes and features in it.

What's next for the XPath API in JAXP?

Posted by spericas on January 5, 2007 at 1:14 PM PST

The XPath API has been part of JAXP since version 1.3, which is part of Java SE 5.0. Yet, we've never received (or at least I haven't heard) much feedback about it or the implementation that we have in the RI. Well, that's not entirely true, I have heard a few times that the implementation is not very fast (which is true), yet not much about the API itself.

Simplifying the JAXP API

Posted by spericas on December 15, 2006 at 7:43 AM PST

One of the complains about the JAXP API that we are hearing (rather loudly!) is number of lines of code that are needed to implement a simple task: you need to instantiate a factory, create an instance from the factory, wrap your parameters in Sources and Results and finally carry out the task. Ah, and don't forget to catch all those exceptions or your code won't even compile.

JAXP 1.4 FCS is available now!

Posted by spericas on December 5, 2006 at 7:21 AM PST

The First Customer Shipment (FCS) version of JAXP 1.4 Reference Implementation (RI) is now available from

Sun Tech Days in Buenos Aires

Posted by spericas on October 26, 2006 at 6:17 AM PDT

The Sun Tech Days in Buenos Aires, Argentina was a fantastic event: great venue (Hilton Puerto Madero), great city (well, my home town so I'm biased) and absolutely fantastic food. Oh, yes, and also really good technical sessions.

Japex plugin for Hudson

Posted by spericas on September 1, 2006 at 11:26 AM PDT

Kohsuke has recently blogged about Hudson plugins and also about the plugin that we have recently wrote for Japex. Here are some more details on how to get up to speed with performance tracking using Japex and Hudson.

Trend Reports in Japex

Posted by spericas on August 18, 2006 at 2:30 PM PDT

Back in April, I blogged about using the Japex regression tracking tool to monitor performance over time. This tool computes a diff between the last two reports and sends alerts via e-mail if a regression (or a progression) higher than a threshold is detected.

Conditional Processing in Japex

Posted by spericas on August 11, 2006 at 1:30 PM PDT

It has been a while since my last blog about Japex. I'm currently working on a couple of improvements: the first involves cleaning up and simplifying the Japex trend reporting tool (but more on this on a later installment) and the second is about conditional processing in configuration files, the topic I would like to talk about today.

Finding Factory Classes in JAXP

Posted by spericas on August 4, 2006 at 12:29 PM PDT

The JAXP API defines a pluggability layer which allows easy swapping of implementations via the use of system properties and meta-information stored in JAR files. I have recently found that the mechanism by which factory classes are located and loaded still causes a great deal of confusion.

SJSXP in now in the Maven Repository

Posted by spericas on July 25, 2006 at 2:18 PM PDT

Sun Java Streaming XML Parser (SJSXP) is now available from the Maven repository. This is the FCS version of Sun's StAX parser.