The sample code below will call the IsomorphicCopy method which call memcpy on the overlapping memory.

     BufferedImage img = new BufferedImage(100, 100, BufferedImage.TYPE_INT_ARGB_PRE);
     Graphics2D g = img.createGraphics();
     g.setComposite(AlphaComposite.Src);
     g.drawImage(img, 0, 0, null);
     g.dispose();

http://linux.die.net/man/3/memcpy
"The memcpy() function copies n bytes from memory area src to memory area dest. The memory areas must not overlap. Use memmove(3) if the memory areas do overlap"