YProlog
YProlog is a pocket Prolog engine written in 100% Java. It provides a number of facilities that enables the Prolog database to be used like an SQL-type database:

YProlog is a successor of XProlog which is a successor of WProlog. YProlog is basically XProlog with extra Prolog-Java interfacing functions. Also, various minor changes were made. The YProlog class provides the Java-Prolog interface (see javadoc).

Older versions

Example programs

YProlog by:
Boris van Schooten
University of Twente
schooten@cs.utwente.nl

XProlog by:
Jean Vaucher
vaucher@iro.umontreal.ca
URL: www.iro.umontreal.ca/~vaucher/XProlog/

WProlog by:
Michael Winikoff
winikoff@cs.rmit.edu.au
URL: http://goanna.cs.rmit.edu.au/~winikoff/wp