JavaHelp
JavaHelp is both an application and a format for online help files that can be displayed by the JavaHelp browser.[1] It is written in Java, and is mainly used in Java applications. It can be used for any application and it does require the overhead of the JRE to load.
The file format is XML.
The GUI uses a tri-pane layout, with a toolbar and menu at the top, navigation pane on the left, and content viewer on the right. The navigation pane includes searching, indexing, and a table of contents.