Полупрозрачная граница JFrame JDK 7

Я задавал вопрос о прозрачной границе JFrame (, см. здесь ), и я получил очень хорошие ответы, но, к сожалению, данные ответы работают отлично только на JDK 6, но не на 7. Есть идеи, как заставить его работать с JDK 7?

В JDK 6 это выглядит так:

И в JDK 7:

И мой код выглядит так:

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.border.AbstractBorder;


public class ShadowBorder extends AbstractBorder {

private static final int RADIUS = 30;
private static BufferedImage shadowTop;
private static BufferedImage shadowRight;
private static BufferedImage shadowBottom;
private static BufferedImage shadowLeft;
private static BufferedImage shadowTopLeft;
private static BufferedImage shadowTopRight;
private static BufferedImage shadowBottomLeft;
private static BufferedImage shadowBottomRight;
private static boolean shadowsLoaded = false;

public ShadowBorder() {
    if (!shadowsLoaded) {
        try {
            shadowTop = ImageIO.read(getClass().getResource("/cz/vutbr/fit/assets/shadow-top.png"));
            shadowRight = ImageIO.read(getClass().getResource("/cz/vutbr/fit/assets/shadow-right.png"));
            shadowBottom = ImageIO.read(getClass().getResource("/cz/vutbr/fit/assets/shadow-bottom.png"));
            shadowLeft = ImageIO.read(getClass().getResource("/cz/vutbr/fit/assets/shadow-left.png"));

            shadowTopLeft = ImageIO.read(getClass().getResource("/cz/vutbr/fit/assets/shadow-top-left.png"));
            shadowTopRight = ImageIO.read(getClass().getResource("/cz/vutbr/fit/assets/shadow-top-right.png"));
            shadowBottomLeft = ImageIO.read(getClass().getResource("/cz/vutbr/fit/assets/shadow-bottom-left.png"));
            shadowBottomRight = ImageIO.read(getClass().getResource("/cz/vutbr/fit/assets/shadow-bottom-right.png"));

            shadowsLoaded = true;
        } catch (IOException ex) {
            Logger.getLogger(ShadowBorder.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

@Override
public boolean isBorderOpaque() {
    return false;
}

@Override
public Insets getBorderInsets(Component c) {
    return new Insets(RADIUS, RADIUS, RADIUS, RADIUS);
}

@Override
public Insets getBorderInsets(Component c, Insets insets) {
    insets.top = RADIUS;
    insets.left = RADIUS;
    insets.bottom = RADIUS;
    insets.right = RADIUS;

    return insets;
}

@Override
public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) {
    Graphics2D g2d = (Graphics2D) g.create();
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

    g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.DST_ATOP, 1f));

    int recWidth = width - (2 * RADIUS);
    int recHeight = height - (2 * RADIUS);
    int recX = width - RADIUS;
    int recY = height - RADIUS;

    //edges
    g2d.drawImage(shadowTop.getScaledInstance(recWidth, RADIUS, Image.SCALE_REPLICATE), RADIUS, 0, null);
    g2d.drawImage(shadowRight.getScaledInstance(RADIUS, recHeight, Image.SCALE_REPLICATE), recX, RADIUS, null);
    g2d.drawImage(shadowBottom.getScaledInstance(recWidth, RADIUS, Image.SCALE_REPLICATE), RADIUS, recY, null);
    g2d.drawImage(shadowLeft.getScaledInstance(RADIUS, recHeight, Image.SCALE_REPLICATE), 0, RADIUS, null);

    //corners
    g2d.drawImage(shadowTopLeft, 0, 0, null);
    g2d.drawImage(shadowTopRight, recX, 0, null);
    g2d.drawImage(shadowBottomLeft, 0, recY, null);
    g2d.drawImage(shadowBottomRight, recX, recY, null);

}
}

Большое спасибо!