Need advice concerning memory usage

Question

Hi all,
i have a class that represents a hexagon map (extends JPanel). This map is usually put in a scrollpane.
In the paintComponent method of the class the hexagons of the map are painted. For good scrolling and painting performance i use the clipping region to paint only the hexagons that are currently visible.
For that purpose i call "hexBounds = hex.getBounds();" to get the bounds of the hexagon. Then i check whether the hexagon's bounds intersect with the clipping region to decide whether the hexagon needs to be painted (see the code below).
The "problem" is that lots of Rectangle objects are created (and memory allocated). So when i render a large map and do some excessive scrolling (which causes lots of repaints) for let's say 1 minute, there are several hundred thousand Rectangle objects that have been allocated (but are no longer referenced) and are occupying up to 20-40 MB of memory. I used the profiler with the following parameters:
-Xint -Xrunhprof:heap=sites,depth=10.
My question is: Do i need to worry about this or will the garbage collector take care of it when it needs to? I could call the garbage collector manually at the beginning of the paintComponent method so that all old, unreferenced Rectangle objects are garbage collected but i've read in several articles that calling the garbage collector manually is generally a bad idea.
What is the best practice in such a case?
Here is the painting code:
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D)g;
        Rectangle clipBounds = g2d.getClipBounds();
        Rectangle hexBounds = null;
        Iterator<Entry<HexagonCoordinates, Hexagon>> iter = hexagons.entrySet().iterator();
        while(iter.hasNext())
            Entry<HexagonCoordinates, Hexagon> entry = iter.next();
            Hexagon hex = entry.getValue();
            hexBounds = hex.getBounds(); // <-- problem
            // Paint only if neccessary
            if(clipBounds.intersects(hexBounds))
                g2d.drawPolygon(hex);
            hexBounds = null;
        }

Answer 1

I've run several tests now and it seems as if the garbage collector takes care of the problem as expected. But what if someone would scroll excessively for many minutes (hey, you know users do strange things sometimes). This would result in more and more memory being allocated in a very short time period. My guess is that the garbage collector would free the occupied memory before the VM runs out of memory, right?
Then everything would be fine.
Any other suggestions on improving my painting code are greatly appreciated.