A Flexible and Easy-to-Use Library for the Rapid Development of Graph Tools in Java.

We present a programming library for the rapid development of graph tools, with applications in graph transformation and related fields. Features include working with graphs, graph morphisms, basic categorical constructions such as computing pushouts and pushout complements or enumerating all morphisms with certain properties, but also applications such as executing graph transformation steps. Additionally, we offer graphical user interface widgets for visualization and manipulation of graphs, morphisms and categorical diagrams.