Java Code:
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.DirectColorModel;
import java.awt.image.IndexColorModel;
import java.awt.image.WritableRaster;

import org.eclipse.swt.SWT;
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.Point;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;

public class Snippet156 {

  static BufferedImage convertToAWT(ImageData data) {
    ColorModel colorModel = null;
    PaletteData palette = data.palette;
    if (palette.isDirect) {
      colorModel = new DirectColorModel(data.depth, palette.redMask,
          palette.greenMask, palette.blueMask);
      BufferedImage bufferedImage = new BufferedImage(colorModel,
          colorModel.createCompatibleWritableRaster(data.width,
              data.height), false, null);
      WritableRaster raster = bufferedImage.getRaster();
      int[] pixelArray = new int[3];
      for (int y = 0; y < data.height; y++) {
        for (int x = 0; x < data.width; x++) {
          int pixel = data.getPixel(x, y);
          RGB rgb = palette.getRGB(pixel);
          pixelArray[0] = rgb.red;
          pixelArray[1] = rgb.green;
          pixelArray[2] = rgb.blue;
          raster.setPixels(x, y, 1, 1, pixelArray);
        }
      }
      return bufferedImage;
    } else {
      RGB[] rgbs = palette.getRGBs();
      byte[] red = new byte[rgbs.length];
      byte[] green = new byte[rgbs.length];
      byte[] blue = new byte[rgbs.length];
      for (int i = 0; i < rgbs.length; i++) {
        RGB rgb = rgbs[i];
        red[i] = (byte) rgb.red;
        green[i] = (byte) rgb.green;
        blue[i] = (byte) rgb.blue;
      }
      if (data.transparentPixel != -1) {
        colorModel = new IndexColorModel(data.depth, rgbs.length, red,
            green, blue, data.transparentPixel);
      } else {
        colorModel = new IndexColorModel(data.depth, rgbs.length, red,
            green, blue);
      }
      BufferedImage bufferedImage = new BufferedImage(colorModel,
          colorModel.createCompatibleWritableRaster(data.width,
              data.height), false, null);
      WritableRaster raster = bufferedImage.getRaster();
      int[] pixelArray = new int[1];
      for (int y = 0; y < data.height; y++) {
        for (int x = 0; x < data.width; x++) {
          int pixel = data.getPixel(x, y);
          pixelArray[0] = pixel;
          raster.setPixel(x, y, pixelArray);
        }
      }
      return bufferedImage;
    }
  }

  static ImageData convertToSWT(BufferedImage bufferedImage) {
    if (bufferedImage.getColorModel() instanceof DirectColorModel) {
      DirectColorModel colorModel = (DirectColorModel) bufferedImage
          .getColorModel();
      PaletteData palette = new PaletteData(colorModel.getRedMask(),
          colorModel.getGreenMask(), colorModel.getBlueMask());
      ImageData data = new ImageData(bufferedImage.getWidth(),
          bufferedImage.getHeight(), colorModel.getPixelSize(),
          palette);
      WritableRaster raster = bufferedImage.getRaster();
      int[] pixelArray = new int[3];
      for (int y = 0; y < data.height; y++) {
        for (int x = 0; x < data.width; x++) {
          raster.getPixel(x, y, pixelArray);
          int pixel = palette.getPixel(new RGB(pixelArray[0],
              pixelArray[1], pixelArray[2]));
          data.setPixel(x, y, pixel);
        }
      }
      return data;
    } else if (bufferedImage.getColorModel() instanceof IndexColorModel) {
      IndexColorModel colorModel = (IndexColorModel) bufferedImage
          .getColorModel();
      int size = colorModel.getMapSize();
      byte[] reds = new byte[size];
      byte[] greens = new byte[size];
      byte[] blues = new byte[size];
      colorModel.getReds(reds);
      colorModel.getGreens(greens);
      colorModel.getBlues(blues);
      RGB[] rgbs = new RGB[size];
      for (int i = 0; i < rgbs.length; i++) {
        rgbs[i] = new RGB(reds[i] & 0xFF, greens[i] & 0xFF,
            blues[i] & 0xFF);
      }
      PaletteData palette = new PaletteData(rgbs);
      ImageData data = new ImageData(bufferedImage.getWidth(),
          bufferedImage.getHeight(), colorModel.getPixelSize(),
          palette);
      data.transparentPixel = colorModel.getTransparentPixel();
      WritableRaster raster = bufferedImage.getRaster();
      int[] pixelArray = new int[1];
      for (int y = 0; y < data.height; y++) {
        for (int x = 0; x < data.width; x++) {
          raster.getPixel(x, y, pixelArray);
          data.setPixel(x, y, pixelArray[0]);
        }
      }
      return data;
    }
    return null;
  }

  static ImageData createSampleImage(Display display) {
    Image image = new Image(display, 100, 100);
    Rectangle bounds = image.getBounds();
    GC gc = new GC(image);
    gc.setBackground(display.getSystemColor(SWT.COLOR_BLUE));
    gc.fillRectangle(bounds);
    gc.setBackground(display.getSystemColor(SWT.COLOR_GREEN));
    gc.fillOval(0, 0, bounds.width, bounds.height);
    gc.setForeground(display.getSystemColor(SWT.COLOR_RED));
    gc.drawLine(0, 0, bounds.width, bounds.height);
    gc.drawLine(bounds.width, 0, 0, bounds.height);
    gc.dispose();
    ImageData data = image.getImageData();
    image.dispose();
    return data;
  }

  public static void main(String[] args) {
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("SWT Image");
    ImageData data;
    if (args.length > 0) {
      String fileName = args[0];
      data = new ImageData(fileName);
    } else {
      data = createSampleImage(display);
    }
    final Image swtImage = new Image(display, data);
    final BufferedImage awtImage = convertToAWT(data);
    final Image swtImage2 = new Image(display, convertToSWT(awtImage));
    shell.addListener(SWT.Paint, new Listener() {
      public void handleEvent(Event e) {
        int y = 10;
        if (swtImage != null) {
          e.gc.drawImage(swtImage, 10, y);
          y += swtImage.getBounds().height + 10;
        }
        if (swtImage2 != null) {
          e.gc.drawImage(swtImage2, 10, y);
        }
      }
    });
    Frame frame = new Frame() {
      public void paint(Graphics g) {
        Insets insets = getInsets();
        if (awtImage != null) {
          g.drawImage(awtImage, 10 + insets.left, 10 + insets.top,
              null);
        }
      }
    };
    frame.setTitle("AWT Image");
    shell.setLocation(50, 50);
    Rectangle bounds = swtImage.getBounds();
    shell.setSize(bounds.width + 50, bounds.height * 2 + 100);
    Point size = shell.getSize();
    Point location = shell.getLocation();
    Insets insets = frame.getInsets();
    frame.setLocation(location.x + size.x + 10, location.y);
    frame.setSize(size.x - (insets.left + insets.right), size.y
        - (insets.top + insets.bottom));
    frame.setVisible(true);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    if (swtImage != null)
      swtImage.dispose();
    if (swtImage2 != null)
      swtImage.dispose();
    frame.dispose();
    System.exit(0);
  }
}