Cross-platform and multi-purpose XML editor, XSLT debugger and Visual Schema Editor. Provides editing support for XML, DTD, XHTML, XSLT, XSD, XML RelaxNG, SVG, MathML and XSL FO [Commercial, 30-day trial].

A XML editor written in Java2 that can be specialize for a set of DTD. It is based on a existing project MerlotXML. [Open source]

A graphical Java XML editor customizable with an XML schema and a file describing the menus to insert the elements. [Open source, GPL]

XML editor plugin for Netbeans, the open source Java IDE. Supports both text mode and tree mode editing. [Open Source]

Tree-mode and text-mode XML editor with color-coding. Can read DTDs and many types of schemas to enhance editing. Built-in support for Cocoon sitemap files, Ant build files and XML Schemas. [Open Source, BSD-like]

Tools for building XML-enabled Java/J2EE applications, including a JSP 1.0/2.0 editor, Java IDE, support for Java XML components including Xalan, Xerces, Saxon, and Java Web services. [Commercial]

Java-based XML editor that supports DTD validation. [Commercial]

Very good editor for structured documents (like DocBook XML). DTD-only version is free to use and comes with DocBook support. XML Schema enabled version is commercial available.

An XML editor for data oriented documents. Editing is guided by any DTD or RELAX NG schema. [Open Source, BSD-like]