chapter 12, "Distributed computing", is available in PDF form from
http://www.oreilly.com/catalog/javapt2/chapter/index.html Chapter 4 from the 1st edition is available in HTML form at
http://www.oreilly.com/catalog/javapt/chapter/ch04.html Of course the 2nd edition is updated with a lot more about Reference objects, but that's life.
Avi's ref is for Joshua Bloch's Effective Java, which is another very good book, though not specifically about Java performance. Of course I prefer mine, but I'm sure Joshua prefers his.
The chapters fom Safari are only previews, unless you open an account. But I think there is a preview of every section of every chapter, so if you want to read a bit of lot's of the book, that's one way to go.
--Jack Shirazi
JavaPerformanceTuning.com