Dungine: a Java Dung Reasoner. Dungine is an open source Argumentation Engine and API implemented in the Java programming language. Dungine uses argument games to evaluate the acceptability of an argument given a constellation of arguments under grounded (sceptical) and preferred credulous semantics. Existing argumentation engines all rely on a companion logic programming language. These companion languages represent a barrier to integrating an engine into existing software as developers must translate their system into the companion logic programming language. Dungine is liberal in its notion of an Argument and this flexible approach overcomes this barrier, and makes integrating argumentation based reasoning into existing software comparatively easy. To demonstrate the usefulness of this approach, and its ease of application, we describe an integration of Dungine with Araucaria-an open source argument mapping tool.