JIProlog is a Prolog interpreter, pure Java 100%, cross-platform and Open Source. JIProlog offers a high degree of compliance with official and de facto Prolog standards. It also supports built-in predicates and other features common to major Prolog systems. JIProlog enhances the Java platform by adding the power of Prolog language and extends Prolog by adding the Java framework. JIProlog integrates Prolog and Java languages in a very fashinating way. It allows calling Prolog predicates from Java without dealing with native code (JNI) and allows invoking Java methods from Prolog as they were predicates. JIProlog supplies a complete API to link Prolog and Java languages from both sides. The API can is composed of three parts: Java calls Prolog; Prolog calls Java; Prolog links JDBC databases. By design, JIProlog is compliant with Web 3.0 and the mobile world.