JinnIde is a plugin that allows using Jinni Prolog, now also hosted here on this site (with open source license!), within the confines of an IDE integrated in JEdit.
HyperSpider (Java app) collects the link structure of a website. Data import/export from/to database and CSV-files. Export to Graphviz DOT, Resource Description Framework (RDF/DC), XML Topic Maps (XTM), Prolog, HTML. Visualization as hierarchy and map.