The ECLiPSe Constraint Logic Programming System is designed for solving combinatorial optimization problems, for the development of new constraint solver technology and their hybrids, and for the teaching of modelling, solving and search techniques.
The Yap Prolog System is a ISO-compatible high-performance Prolog compiler. Yap is widely considered one of the fastest available Prolog systems. Yap supports coroutining, CLP(QR), CHR, and depth-bound search. Tabling and parallelism are in development.
...THE PROJECT HAS BEEN MOVED TO GITHUB
https://github.com/jiprolog/
JIProlog is a cross-platform pure Java 100% Prolog interpreter that integrates Prolog and Java languages in a very fashinating way.
JIProlog is compliant with the major Prolog interpreters. It supports most of ISO Prolog specifications and the most common and used built-in predicates,
JIProlog allows to call Prolog predicates from Java without dealing with native code (JNI or JNA) and allows to invoke Java methods from Prolog in the same way you call predicates.