Program: 45943
Project: 45943
Buggy source:
@Override public String importFile(File file,String extension){
  final JFrame frame=JmeClientMain.getFrame().getFrame();
  if (isContentExists(file) == true) {
    int result=JOptionPane.showConfirmDialog(frame,"String_Node_Str" + file.getName() + "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str","String_Node_Str",JOptionPane.YES_NO_OPTION);
    if (result == JOptionPane.NO_OPTION) {
      return null;
    }
  }
  JOptionPane waitMsg=new JOptionPane("String_Node_Str" + file.getName() + "String_Node_Str");
  final JDialog dialog=waitMsg.createDialog(frame,"String_Node_Str");
  SwingUtilities.invokeLater(new Runnable(){
    public void run(){
      dialog.setVisible(true);
    }
  }
);
  DeployedModel deployedModel;
  try {
    deployedModel=modelUploadContent(file);
  }
 catch (  java.io.IOException excp) {
    logger.log(Level.WARNING,"String_Node_Str" + file.getAbsolutePath(),excp);
    final String fileName=file.getName();
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        dialog.setVisible(false);
        JOptionPane.showMessageDialog(frame,"String_Node_Str" + fileName,"String_Node_Str",JOptionPane.ERROR_MESSAGE);
      }
    }
);
    return null;
  }
  SwingUtilities.invokeLater(new Runnable(){
    public void run(){
      dialog.setVisible(false);
    }
  }
);
  createCell(deployedModel);
  return deployedModel.getDeployedURL();
}

Fixed version (ground truth):
@Override public String importFile(File file,String extension){
  final JFrame frame=JmeClientMain.getFrame().getFrame();
  int result=JOptionPane.YES_OPTION;
  ContentResource resource=isContentExists(file);
  if (resource != null) {
    Object[] options={"String_Node_Str","String_Node_Str","String_Node_Str"};
    String msg="String_Node_Str" + file.getName() + "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str";
    String title="String_Node_Str";
    result=JOptionPane.showOptionDialog(frame,msg,title,JOptionPane.YES_NO_CANCEL_OPTION,JOptionPane.QUESTION_MESSAGE,null,options,options[0]);
    if (result == JOptionPane.CANCEL_OPTION || result == JOptionPane.CLOSED_OPTION) {
      return null;
    }
  }
  if (result == JOptionPane.NO_OPTION) {
    URL url=null;
    try {
      url=resource.getURL();
      LoaderManager manager=LoaderManager.getLoaderManager();
      DeployedModel dm=manager.getLoaderFromDeployment(url);
      createCell(dm);
      return dm.getDeployedURL();
    }
 catch (    java.lang.Exception excp) {
      logger.log(Level.WARNING,"String_Node_Str" + url,excp);
      JOptionPane.showMessageDialog(frame,"String_Node_Str" + file.getAbsolutePath(),"String_Node_Str",JOptionPane.ERROR_MESSAGE);
      return null;
    }
  }
  JOptionPane waitMsg=new JOptionPane("String_Node_Str" + file.getName() + "String_Node_Str");
  final JDialog dialog=waitMsg.createDialog(frame,"String_Node_Str");
  SwingUtilities.invokeLater(new Runnable(){
    public void run(){
      dialog.setVisible(true);
    }
  }
);
  DeployedModel deployedModel;
  try {
    deployedModel=modelUploadContent(file);
  }
 catch (  java.io.IOException excp) {
    logger.log(Level.WARNING,"String_Node_Str" + file.getAbsolutePath(),excp);
    final String fileName=file.getName();
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        dialog.setVisible(false);
        JOptionPane.showMessageDialog(frame,"String_Node_Str" + fileName,"String_Node_Str",JOptionPane.ERROR_MESSAGE);
      }
    }
);
    return null;
  }
 finally {
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        dialog.setVisible(false);
      }
    }
);
  }
  createCell(deployedModel);
  return deployedModel.getDeployedURL();
}