RenderingHints renderingHints = new RenderingHints(
RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
AffineTransformOp scaleOp = new AffineTransformOp(
AffineTransform.getScaleInstance(scale, scale), renderingHints);
BufferedImage targetImage = new BufferedImage(
(int)(image.getWidth() * scale),
(int)(image.getHeight() * scale), image.getType());
scaleOp.filter(image, targetImage);
return targetImage;
}

public static void main(String[] args)

