The constraint programming technology has matured to the point where it is possible to isolate some essential features and offer them as libraries or embedded cleanly in general purpose host programming languages.
For example ILOG Solver is for planning or scheduling systems. Now I am trying to use Constraint Programming Satisfy (CPS) and domain specific language (DSL) at scheduling system.

1. JaCoP – Java Constraint Programming solver
2. Cream: Class Library for Constraint Programming in Java
3. jOpt is an open source implementation of the Optimization Programming Language
4. JACK: A Java Constraint Kit
5. ILOG CP Optimizer
6. Koalog Constraint Solver
7. Open Source Constraint Programming Solvers Written in Java (collections)

1. Magazine: Journal of Scheduling
2. Constraint Programming in Java with JSolver (ILOG)
3. Course: CS 886: Topics in Artificial Intelligence: Constraint Programming
4. Course: Programming with Constraints: an Introduction
6. Course: Constraint Programming: Services
7. Book: Programming with constraints
8. Book: Handbook of constraint programming
9. Solving Sudokus in Java