Main.java

import java.awt.{Color, Graphics2D}
import java.awt.image.BufferedImage
import javax.imageio.ImageIO

public class Main {

  //Does not deal with double buffering, and writing on servers which are headless.
  public BufferedImage createBlackImage(int width, int height) {
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    Graphics2D graphics = (Graphics2D) image.getGraphics();
    graphics.setBackground(Color.BLACK);
    graphics.drawRect(0, 0, width, height);
    return image;
  }

  public static void main(String[] args) {
    ImageIO.write(createBlackImage(100, 100), "png", new java.io.File(args[0]));
  }
}