No longer relevant thanks to Eclipse framework
Now that Eclipse has an open source (LGPL) framework for building compilers, processors, refactoring tools, code generators, and interpreters, this book is hardly relevant. Eclipse's JDT is well documented, and functionality existing for Java can be ported to other languages (and some is already abstracted to the underlying Eclipse platform). Eclipse has an AST (Abstract Syntax Tree), DOM, and all the other tools this book hacks together, except Eclipse is a huge widely supported open source project.