You can see that there was a sharp uptick in Java book sales starting in July of 2004 -- Java's share of all programming books sold is up about 3% since June of '04. A lot of this growth spurt occurred shortly after JavaOne and the new Tiger release, which happened around that time. All of the top titles were revised, and saw a healthy sales increase as a result. However, when we analyzed new books (versus revisions), it appears that a substantial portion of Java's sustained growth, outside of the classic titles, has come from books on Open Source Java projects, such as Spring, Struts, Lucene, and AspectJ, which collectively performed at nearly double the unit and revenue volumes of new books on their non-Open Source counterparts.
These results indicate that a lot is happening in the Open Source Java community, at least on the book side. To support this positive trend, we've devoted a whole track to Open Java at this year's OSCON, to be held August 1-5 in Portland, OR. And of course, we're continuing our usual strong coverage of PHP, Perl, Python, and Ruby.