Java Code:
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.PaletteData;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class Snippet70 {

  public static void main(String[] args) {
    Display display = new Display();
    Color red = display.getSystemColor(SWT.COLOR_RED);
    Color white = display.getSystemColor(SWT.COLOR_WHITE);
    Color black = display.getSystemColor(SWT.COLOR_BLACK);

    Image image = new Image(display, 20, 20);
    GC gc = new GC(image);
    gc.setBackground(red);
    gc.fillRectangle(5, 5, 10, 10);
    gc.dispose();
    ImageData imageData = image.getImageData();

    PaletteData palette = new PaletteData(new RGB[] { new RGB(0, 0, 0),
        new RGB(0xFF, 0xFF, 0xFF), });
    ImageData maskData = new ImageData(20, 20, 1, palette);
    Image mask = new Image(display, maskData);
    gc = new GC(mask);
    gc.setBackground(black);
    gc.fillRectangle(0, 0, 20, 20);
    gc.setBackground(white);
    gc.fillRectangle(5, 5, 10, 10);
    gc.dispose();
    maskData = mask.getImageData();

    Image icon = new Image(display, imageData, maskData);
    Shell shell = new Shell(display);
    Button button = new Button(shell, SWT.PUSH);
    button.setImage(icon);
    button.setSize(60, 60);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    icon.dispose();
    image.dispose();
    mask.dispose();
    display.dispose();
  }
}