Kal Ahmed (Techquila.com) announced that "version 0.4 of TM4J, the open source topic map engine for Java programmers is now available from www.techquila.com. There have been a lot of changes from the 0.3 release, most important of which is support for reading and writing files in the XML Topic Maps (XTM) format, but the new download also includes several sample applications including an experimental topic map navigation application."
TM4J -- A Topic Map Engine For Java -- "is a small suite of Java packages which provide interfaces and default implementations for the import, manipulation and export of Topic Maps encoded to conform to the XTM (XML Topic Maps) DTD. This is the fourth public release of TM4J and it is significantly different from the previous releases. Most important change is that TM4J now supports XTM (and currently only XTM) as the XML format that it reads and writes. The JAR file tmp3.jar contains a simple topic-map generating application based on TM4J and Jens Vonderheide's MP3 library. TM4J implements a Topic Map architecture using the XTM syntax defined and specified by Topicmaps.Org. The ISO specification for Topic Navigation Maps is not supported by TM4J in this release -- I do have plans to add an import and export filter capable of producing ISO conformant XML files. An updated tutorial on using TM4J, TMNav and TMP3 will be posted shortly. Binary and source distributions are available for download; terms are based on the Apache Software Foundation license. The licensing for TM4J is based on the Apache Software Foundation license."
XML Topic Maps are being defined formally by TopicMaps.Org working groups. TopicMaps.Org is an independent consortium of parties developing the applicability of the topic map paradigm [ISO13250] to the World Wide Web by leveraging the XML family of specifications. The latest AG review specification describes version 1.0 of XML Topic Maps (XTM) 1.0, an abstract model and XML grammar for interchanging Web-based topic maps, written by the members of the TopicMaps.Org Authoring Group. Abstract: "This specification provides a model and grammar for representing the structure of information resources used to define topics, and the associations (relationships) between topics. Names, resources, and relationships are said to be characteristics of abstract subjects, which are called topics. Topics have their characteristics within scopes: i.e., the limited contexts within which the names and resources are regarded as their name, resource, and relationship characteristics. One or more interrelated documents employing this grammar is called a 'topic map'."