Gecode/J is a Java interface for the Gecode C++ constraint programming library. It allows you to
model and solve
constraint problems in Java.
explore the search tree
with Gist, the Graphical Interactive Search Tool. Either using the built-in depth-first search strategy, or manually and interactively. Solutions and choice nodes can be inspected by clicking on them, and visualized using custom actions.
implement propagators
in Java. Whether for prototyping, for teaching, or just for fun. The propagators are integrated fully, so in your model you can mix them freely with the built-in propagators provided by Gecode.
implement branchings
for custom heuristics. Just like propagators, custom branchings fully integrate into Gecode/J.
implement search engines
using copying and recomputation. As search is fully programmable, you can write your own search engine, e.g. for LDS or A* search. In fact, Gist is implemented entirely in Java using the Gecode/J interface.