JIProlog integrates Prolog and Java languages in a very easy way allowing to call Prolog predicates from Java without dealing with native code (JNI) and allowing to invoke Java methods from Prolog in the same way you call predicates. JIProlog is designed to work with any Java 1.1 platform or later, including Java enabled application servers, Java enabled browsers, PDAs compliant with Personal Java 1.1 and mobile devices compliant with MIDP 1.0/2.0. JIProlog is supplied with powerfull Integrated Devopment Environment to edit, consult, run and test Prolog programs and provides a set of java classes, that forms the JIProlog API, which allows to: - call Prolog Predicates from Java without dealing with native code and JNI; - call Java methods and classes from Prolog without dealing with foreign language interfaces; - write custom Prolog predicates in Java in order to extend the default set of built-in predicates; - extend the graphical user interface of a Prolog program implementing windows and dialogs in Java as custom predicates; - integrate databases in Prolog through a JDBC Prolog bridge, treating tables and views as Prolog predicates.