String name = null;
Optional<String> opt = Optional.ofNullable(name);

opt.ifPresent(n -> System.out.println("Привет, " + n));

String safeName = opt.orElse("Гость");
System.out.println(safeName); // Гость

String upper = opt.map(String::toUpperCase).orElse("UNKNOWN");
System.out.println(upper);

BufferedImage img = ImageIO.read(new File("input.jpg"))
for (x, y in pixels) {
    int rgb = img.getRGB(x, y)
    int r = (rgb >> 16) & 0xFF
    int g = (rgb >> 8) & 0xFF
    int b = rgb & 0xFF

int gray = (r + g + b) / 3
img.setRGB(x, y, (gray << 16) | (gray << 8) | gray)
}

ImageIO.write(img, "jpg", new File("output.jpg"))