Need help fast about opening file

Question

hello i have this 2 classes to open file and display it .the open method works fine but when ever i try to open different file it adds the new data and display both . the problem is it not suppose to add the new data to the old list it should only show the new data only ...can any one help thx
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class RoomGUI extends JFrame
   private RoomSortedList list;
     // Menu items:
   private JMenuItem mOpen;
   private JMenuItem mSaveAs;
   private JMenuItem mExit;
     // Displayed regions of the window:
     private JTextField messageField;
     private JTextArea textArea;
      * Constructor for RoomGUI object to set up
      * GUI window with menu.
     public RoomGUI()
          list=new RoomSortedList();     
     // Components to display on window:
          messageField = new JTextField();
          messageField.setEditable(false);
          textArea = new JTextArea();
          textArea.setEditable(false); 
                    // Arrnge components on window:
          Container contentPane = getContentPane();
          contentPane.add(messageField, BorderLayout.SOUTH);
          JPanel centerPanel = new JPanel();
          contentPane.add(centerPanel, BorderLayout.CENTER);
          centerPanel.setLayout(new GridLayout(1,1));
          centerPanel.add(new JScrollPane(textArea));
//  Create menu items for the "File" menu:
      mOpen = new JMenuItem ("Open");
      mSaveAs = new JMenuItem ("SaveAs");
      mExit = new JMenuItem ("Exit");
      //  Create "File" menu:
      JMenu fileMenu = new JMenu ("File", /*tearoff =*/ false);
      fileMenu.add(mOpen);
      fileMenu.add(mSaveAs);
      fileMenu.add(mExit);
      // Create menu bar:
      JMenuBar mainMenuBar = new JMenuBar();
      mainMenuBar.add(fileMenu);
      // Put menu bar on this window:
      setJMenuBar(mainMenuBar);
     mOpen.addActionListener( new FileOpener(textArea,list) );
     mSaveAs.addActionListener( new FileSaver(list) );
      mExit.addActionListener(new Quitter());
          // Routine necessities with JFrame windows:
          setSize(500, 400);
          setLocation(200, 100);
          setTitle("Project 4");
          setDefaultCloseOperation(EXIT_ON_CLOSE);
          setVisible(true);
     } // constructorfile opener
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class FileOpener implements ActionListener
     private RoomSortedList list;
     private JTextArea textArea=new JTextArea();
          private int returnvalue;
          private String filename;
          private JTextField messageField;
     public FileOpener(JTextArea ta,RoomSortedList ls)
          this.textArea=ta;
          this.list=ls;
     public void actionPerformed(ActionEvent e)
          list =new RoomSortedList();
          messageField = new JTextField();
          JFileChooser filechooser = new JFileChooser();
         // if a file is selected returnvalue = 0
         // else if cancel button is pressed
         // returnvalue = 1
         returnvalue = filechooser.showOpenDialog(null);
         //if open is selected then return filename
         if (returnvalue == filechooser.APPROVE_OPTION){
            filename = filechooser.getSelectedFile().toString();
            // now read the rooms from the file with the name filename
            // invoke the readfile method
            readFile(filename);
            messageField.setText(filename);
         }//if
         // if cancel is selected then close the filechooser
         else if (returnvalue == filechooser.CANCEL_OPTION)
            filechooser.cancelSelection();
   * Reads room data from a text file.Check if each lines are in valid room
   * format, and values. Catches exception errors for any invalid lines or
   * values thrown by ParseRoom or Room constructors.
   * Valid lines are appended to an sorted linked list. 
   * @param filename     name of file containing
   private void readFile(String filename)
       JFrame errorD=new JFrame();
      String str=null;
      Room r=null;
      int linenum=0;
      TextFileInput Obj=null;
      try
         Obj = new TextFileInput(filename);
      catch (RuntimeException rte)
         System.out.println(rte.getMessage());
      while (true)
         str = Obj.readLine();
         linenum++;
         if (str==null) break; // to stop reading lines at the end of file
         try
            r = RoomTextFormat.parseRoom(str);
         catch (RoomTextFormatException rtf)
            JOptionPane.showMessageDialog(errorD, "Error reading line # " +
               linenum + ": " + str + "\n" + rtf.getMessage() + "\n"+
               "This line of text has been excluded from the list.",
               "Text Format Error", JOptionPane.ERROR_MESSAGE);
            continue;
         catch (IllegalRoomException ire)
            JOptionPane.showMessageDialog(errorD, "Error reading line # " +
               linenum + ": " + str + "\n" + ire.getMessage() + "\n" +
               "This line of text has been excluded from the list.",
               "Room Instantiation Error", JOptionPane.ERROR_MESSAGE);
            continue;
         list.insert (r);
         textArea.setText("");
            RoomListIterator MyIterator = list.beginIterating();
            int c=1;
            while (MyIterator.hasNext())
               Room m = MyIterator.next();
               textArea.append(c + ": " + m + "\n");
               c++;
            }//while
      }// while (true)
   } // readFile()
}

Answer 1

i apologize again.thx anyway . heres the code
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class RoomGUI extends JFrame
     private RoomSortedList list;
     // Menu items:
     private JMenuItem mOpen;\
     // Displayed regions of the window:
     private JTextField messageField;
     private JTextArea textArea;
      * Constructor for RoomGUI object to set up
      * GUI window with menu.
     public RoomGUI()
          list=new RoomSortedList();     
          // Components to display on window:
          messageField = new JTextField();
          messageField.setEditable(false);
          textArea = new JTextArea();
          textArea.setEditable(false); 
          // Arrnge components on window:
          Container contentPane = getContentPane();
          contentPane.add(messageField, BorderLayout.SOUTH);
          JPanel centerPanel = new JPanel();
          contentPane.add(centerPanel, BorderLayout.CENTER);
          centerPanel.setLayout(new GridLayout(1,1));
          centerPanel.add(new JScrollPane(textArea));
              //Create menu items for the "File" menu:
          mOpen = new JMenuItem ("Open");
          //  Create "File" menu:
          JMenu fileMenu = new JMenu ("File", /*tearoff =*/ false);
          fileMenu.add(mOpen);
          // Create menu bar:
          JMenuBar mainMenuBar = new JMenuBar();
          mainMenuBar.add(fileMenu);
          // Put menu bar on this window:
          setJMenuBar(mainMenuBar);
          mOpen.addActionListener( new FileOpener(textArea,list) );
          setDefaultCloseOperation(EXIT_ON_CLOSE);
          setVisible(true);
     } // constructor
} // class RoomGUIopen file
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class FileOpener implements ActionListener
     private RoomSortedList list;
     private JTextArea textArea=new JTextArea();
          private int returnvalue;
          private String filename;
          private JTextField messageField;
     public FileOpener(JTextArea ta,RoomSortedList ls)
          this.textArea=ta;
          this.list=ls;
     public void actionPerformed(ActionEvent e)
          list =new RoomSortedList();
          messageField = new JTextField();
          JFileChooser filechooser = new JFileChooser();
         // if a file is selected returnvalue = 0
         // else if cancel button is pressed
         // returnvalue = 1
         returnvalue = filechooser.showOpenDialog(null);
         //if open is selected then return filename
         if (returnvalue == filechooser.APPROVE_OPTION){
            filename = filechooser.getSelectedFile().toString();
            readFile(filename);
            messageField.setText(filename);
         }//if
         // if cancel is selected then close the filechooser
         else if (returnvalue == filechooser.CANCEL_OPTION)
            filechooser.cancelSelection();
   private void readFile(String filename)
      String str=null;
      TextFileInput Obj=null;
         Obj = new TextFileInput(filename);
      while (true)
         str = Obj.readLine(); // 
         if (str==null) break; // to stop reading lines at the end of file
         list.insert (str);
         textArea.setText("");
            RoomListIterator MyIterator = list.beginIterating();
            int c=1;
            while (MyIterator.hasNext())
               Room m = MyIterator.next();
               textArea.append(c + ": " + m + "\n");
               c++;
            }//while
      }// while (true)
   } // readFile()
}