Butterfly XML Editor

The Butterfly XML editor is another open source project that provides XML formatting and well-formedness validation. It does not have schema validation. Butterfly's approach to validation results is a bit different that most other packages. Instead of providing error messages with line and column numbers, it highlights the tags in error, and provides the message about the problem embedded in a tree structure representing the document.

The SourceForge project for Butterfly shows no activity since 2004. The source code on SourceForge is incomplete, with several of the main classes missing. From their usage it can be seen that the main XML document class contains the XML as a String, but provides an extensive set of methods that parse nodes from the XML tree.