setBackground函数在Java9中从JD中心移动JDialog / Jframe

Question

我正在使用以下代码来显示启动画面。以下在Java 8中运行良好。但在Java 9中，我观察到闪屏不再位于中心，而是位于左上方。

dialog = new JDialog();
dialog.setModal(false);
dialog.setUndecorated(true);
dialog.getRootPane().setOpaque(false);
dialog.getContentPane().setBackground(new Color(0, 0, 0, 0));
dialog.setBackground(new Color(0, 0, 0, 0));
dialog.setResizable(false);
...
dialog.pack();
dialog.setLocationRelativeTo(null);
dialog.setVisible(true);

我确认问题发生在

dialog.setBackground

但不知道为什么。我尝试使用JFrame并遇到了同样的问题。知道如何在Java 9中修复它吗？

编辑：

以下是完整的代码：

package test;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Image;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.util.Properties;

import javax.swing.ImageIcon;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JProgressBar;

public class SplashScreen
{

    private static JDialog  dialog;
    private String          fImage;

    static JProgressBar     progressBar = new JProgressBar();

    public SplashScreen(String image)
    {
        fImage = image;

    }

    // -------------------------------------------------------------------------------------------
    // hideSplashScreen
    // -------------------------------------------------------------------------------------------
    public void hideSplashScreen()
    {
        dialog.setVisible(false);
        dialog.dispose();
    }

    // -------------------------------------------------------------------------------------------
    // showSplashScreen
    // -------------------------------------------------------------------------------------------
    public static void showSplashScreen() throws MalformedURLException
    {

        dialog = new JDialog();
        dialog.setModal(false);
        dialog.setUndecorated(true);
        dialog.getRootPane().setOpaque(false);
        dialog.getContentPane().setBackground(new Color(0, 0, 0, 0));
        dialog.setBackground(new Color(0, 0, 0, 0));
        dialog.setResizable(false);

        // Scaling down
        Image image = new ImageIcon("C:\\SplashScreen.gif").getImage().getScaledInstance(700, 700, java.awt.Image.SCALE_SMOOTH);

        JLabel background = new JLabel(new ImageIcon(image));
        background.setLayout(new BorderLayout());
        dialog.add(background);

        dialog.add(progressBar, BorderLayout.SOUTH);
        progressBar.setStringPainted(true);
        progressBar.setForeground(new Color(0, 146, 189));

        dialog.pack();
        dialog.setLocationRelativeTo(null);
        dialog.setVisible(true);
    }

    // -------------------------------------------------------------------------------------------
    // readVersion
    // -------------------------------------------------------------------------------------------
    private String readVersion()
    {
        String version = "";
        Properties prop = new Properties();
        try
        {
            InputStream in = SplashScreen.class.getClassLoader().getResourceAsStream("sciome/workbench/resources/version.properties");
            prop.load(in);
            in.close();
            version = prop.getProperty("version");
        }
        catch (IOException e)
        {
            System.err.println(e.getMessage());
        }
        return version;
    }

    // ---------------------------------------------------------------------------------
    // setProgBarVisible
    // ---------------------------------------------------------------------------------
    public void setProgBarVisible(boolean bVisible)
    {
        progressBar.setVisible(bVisible);
    }

    // ---------------------------------------------------------------------------------
    // updateProgBar
    // ---------------------------------------------------------------------------------
    public void updateProgBar(String strDetails, int nProgress)
    {
        progressBar.setValue(nProgress);
        progressBar.setString(strDetails + " (" + nProgress + "% complete).");
    }

    public static void main(String[] args)
    {
        try
        {
            showSplashScreen();
        }
        catch (MalformedURLException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

我使用的是jdk-9.0.1。请确保在测试上述代码时，将类路径更改为jdk-9.0.1以及将编译和构建设置更改为Java 9