Sample

import java.awt.Color;
import java.awt.image.*;

public class sample
{
	
	public BufferedImage draw()
	{
		int WIDTH = 800;
		int HEIGHT = 600;
		int IMG_TYPE = java.awt.image.BufferedImage.TYPE_INT_ARGB;
		
		BufferedImage image = new BufferedImage(WIDTH, HEIGHT, IMG_TYPE);
		
		ColorModel model = image.getColorModel(); 
		WritableRaster raster = image.getRaster();
				
		Color fcolor; 
		
		for(int i = 0; i < WIDTH; i++) 
			for(int j = 0; j < HEIGHT; j++) {
							
				fcolor = new Color((0xffff & (i*j)) << 8 );
			
				raster.setDataElements(i, j, 
						model.getDataElements(fcolor.getRGB(), null));
			
		}
		
		return image;
	}
}