DocFlex/Doclet is a template-driven multi-format Javadoc Doclet. It is a freeware edition of DocFlex/Javadoc -- a programming tool for rapid development of Javadoc-based Java API documentation generators in various output formats (currently: framed/single-file HTML, RTF and TXT). The free edition includes the "DocFlex Doclet" -- the template interpreter / output generator wrapped as a Javadoc doclet, which provides also a little GUI where you can specify all template and output format settings interactively, start the generation, track its progress and stop at any moment.
It includes also two ready template sets:
1) Basic Template Set -- an early version of standard template set, which you can use to generate Java API documentation for any your projects in any of the supported output formats. It is able to generate only basic content: project overview, package summaries, class details. All Java 5 language features are fully supported. The RTF JavaDoc may be of particular importance. It supports also the interpreting in RTF the HTML tags embedded doc-comments. Almost all practically usable HTML tags are supported (including insertion of images specified with <img> tags). You will hardly find any other tool able to generate such a complex RTF!
2) "JavadocPro" Template Set -- implements the most advanced Java API documentation generator with the support of filtering of classes and members by tags/annotations. In the free edition, this template set will work only in limited mode.
However, that will be enough to generate full-blown framed HTML documentation identical to classic JavaDoc (with the same functionality as provided by the standard Javadoc). If you are not a big fan of the new JavaDoc design introduced in Java 7,
you can use JavadocPro templates to generate the classic-looking JavaDoc under Java 7 too. That's free!

Platform: Windows XP, Mac OSX, Linux

System Requirements: JDK 7, JDK 6, JDK 5.0, Java2 SDK 1.4