So here's the deal, i'm parsing a file that contains the vertices for a polygon, that i want to create in box2d. I create a new PolygonShape() and then call .set() giving it a defined array of Vec, and that defined array's .length property. I expected this to work, since the documentation for jbox2d says this method takes a Vec array, and the count of Vec objects in that array. However, it errors out, and it seems to be unrelated to my code. The error i get is Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 8 at org.jbox2d.collision.shapes.PolygonShape.set(PolygonShape.java:174) and, upon looking at that line in the jbox2d svn repository, i still cannot figure out the issue. Any help is appreciated!