A few small improvements to java.awt.geom.Rectangle2D etc..
new Rectangle2D.Double(x, y, w, h)
Is a bit ugly, and I've had a lot of grief from import management tools. Hows about a set of static factory methods with differently typed arguments? Should include ones with Point2D and Dimension2D arguments as well as X, Y, W, H.
This goes for the whole set of java.awt.geom objects, really. Point2D, Line2D etc..
Modification methods are a bit sparse too. How about something like:
public void setSize(Dimension2D newSize, int gravity);
And some translate methods would be nice.
OK, it's sugar but it helps the medicine go down.