import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;

public class App {

    public static void main(String[] args) {

        BufferedImage img = new BufferedImage(256, 256,
                                            BufferedImage.TYPE_INT_RGB);

        int r = (byte)255;
        int g = (byte)10;
        int b = (byte)50;
        int col = (r << 16) | (g << 8) | b;

        for(int i = 0; i < img.getWidth()/2; i++) {

            for(int j = 0; j < img.getHeight()/2; i++) {

                img.setRGB(i, j, col);

            }

        }

        File f = new File("test.png");
        try{
            ImageIO.write(img, "PNG", f);
        } catch(Exception e) {
            System.out.println("Failed");
        }

    }

}