I\'m reading a PNG image with the following code:
BufferedImage img = ImageIO.read(new URL(url));
Upon displaying it, there is a black back
Create a second BufferedImage
of type TYPE_INT_RGB
...
BufferedImage copy = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_INT_RGB);
Paint the original to the copy...
Graphics2D g2d = copy.createGraphics();
g2d.setColor(Color.WHITE); // Or what ever fill color you want...
g2d.fillRect(0, 0, copy.getWidth(), copy.getHeight());
g2d.drawImage(img, 0, 0, null);
g2d.dispose();
You now have a non transparent version of the image...
To save the image, take a look at Writing/Saving an Image