求教JFrame和JDialog的问题

有个需求，在swing的JFrame中有上一条、下一条按钮，点击上一条，关闭当前JFrame，显示JDialog（JDialog中是一个不确定进度条），当下一个JFrame加载好了，关闭JDialog，显示JFrame。
问题是，当下一个JFrame加载完成之前，JDialog处于假死状态，显示不出来不确定进度条，任何文字都不会显示，当JFrame成功显示出来的时候，JDialog才会显示。打不到我想要的效果
求大神赐教，以下是效果图

代码：

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class MainFrame{

private JFrame mf = new JFrame();
private JButton previousRecordButton = null;
private JButton nextRecordButton = null;

public MainFrame(){
    Thread initThread = new Thread(new Runnable() {
        @Override
        public void run() {
            init();
        }
    });
    initThread.start();

    (new WaitDialog(mf, initThread)).start();// 启动等待提示框线程
    mf.setVisible(true);
}

public void init(){
    JPanel mainPane = new JPanel(null);
    previousRecordButton = new JButton("上一条");
    previousRecordButton.setBounds(20, 350, 100, 25);

    nextRecordButton = new JButton("下一条");
    nextRecordButton.setBounds(240, 350, 100, 25);

    previousRecordButton.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent ae) {
            close();
            new DoOpen().open();
        }
    });
    nextRecordButton.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent ae) {
            close();
            new DoOpen().open();
        }
    });


    mainPane.add(previousRecordButton);
    mainPane.add(nextRecordButton);

    mf.add(mainPane);
    // this.setUndecorated(true); // 除去title
    mf.setResizable(true);
    mf.setSize(390, 500);
    mf.setLocationRelativeTo(null); // 设置此窗口相对于指定组件的位置
    mf.setAlwaysOnTop(true);
}

public void close(){
    mf.dispose();
}

}

import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JProgressBar;

/**

• @ClassName: WaitDialog
• @Description: TODO
• @author Wangjj

• @date 2016年8月16日 上午9:09:54
  */
  public class WaitDialog extends Thread {

  private JDialog dialog = null;

  private JLabel lbStatus;

  private JProgressBar progressBar;

  private JFrame parentFrame = null;

  private Thread currentThread = null;

  public WaitDialog(JFrame parentFrame, Thread currentThread) {
  this.parentFrame = parentFrame;
  this.currentThread = currentThread;
  initWaitDialogUI();// 初始化提示框
  }

  /**

  • 构建显示进度条的对话框
    */
    private void initWaitDialogUI() {
    dialog = new JDialog(parentFrame);

    JPanel mainPane = new JPanel(null);

    progressBar = new JProgressBar();
    progressBar.setIndeterminate(true);
    progressBar.setBounds(20, 20, 340, 15);

    lbStatus = new JLabel("正在加载, 请稍后 ...");
    lbStatus.setBounds(20, 60, 350, 25);

    mainPane.add(progressBar);
    mainPane.add(lbStatus);

    dialog.add(mainPane);
    // dialog.setUndecorated(true); // 除去title
    dialog.setModal(false);
    dialog.setResizable(true);
    dialog.setSize(390, 150);
    dialog.setLocationRelativeTo(null); // 设置此窗口相对于指定组件的位置
    (new DisposeWaitDialog(currentThread,dialog)).start();// 启动关闭提示框线程
    }

  public void run(){
  dialog.setAlwaysOnTop(true);
  dialog.setVisible(true);
  }

}

import javax.swing.JDialog;

public class DisposeWaitDialog extends Thread{
private Thread currentThread = null;
private JDialog clueDiag = null;

public DisposeWaitDialog(Thread currentThread, JDialog clueDiag) {
    this.currentThread = currentThread;
    this.clueDiag = clueDiag;
}

public void run() {
    try {
        currentThread.join();
    } catch (InterruptedException e) {
        System.out.println("Exception:" + e);
    }
    clueDiag.dispose();// 关闭提示框
}

}

public class DoOpen {

MainFrame mf = null;

public void open(){
    mf = new MainFrame();
}

public static void main(String[] args) {
    new DoOpen().open();
}

}

这个东西难道不应该把代码贴出来吗？