QDox is a high speed, small footprint parser for extracting class/interface/method definitions from source files complete with JavaDoc @tags. It is designed to be used by active code generators or documentation tools.
In A Nutshell
The parser skims the source files only looking for things of interest such as class/interface definitions, import statements, JavaDoc and member declarations. The parser ignores things such as actual method implementations to avoid overhead (while in method blocks, curly brace counting suffices).
The end result of the parser is a very simple document model containing enough information to be useful.