I am using JTS & I am trying to create a polygon whose shape is determined by a set of other polygons, which are rectangles.  My resulting polygon necessarily wont be rectangle, as it could have missing inner polygons.  All i am interested is the bounding box of the resulting polygon.

I tried Polygonizer & couple of other polygon packers, including "union", all of them gives me same result - they all retain the boundary of inner geometry & the resulting polygon does NOT exclude those missing parts (i am not concerned about the inner holes, only those can be accessed from the outside of the boundary).

I have attached a screenshot, which i think would convey what exactly is my requirement.

Any help is greatly appreciated!