java.io.NotSerializableException when overwrite the JTable data into .txt file

[roger lim shau xiong]

hi everyone

i had java.io.NotSerializableException: java.lang.reflect.Constructor error when overwrite the JTable data into .txt file.
At the beginning, the code will be generate successfully and the jtable will be showing out with the data that been save in the studio1.txt previously,
but after i edit the data at the JTable, and when i trying to click the save button, the error had been showing out and i cannot succeed to save the JTable with the latest data.
After this error, the code can't be run again and i had to copy the studio1.txt again to let the code run 1 more time.
I hope i can get any solution at here and this will be very useful for me.
but i dunno how to attach my .txt file with this forum
did anyone need the .txt file?

i had edit the code and make it simple for reading
this is the objectinput code

   
String filename1="studio1.txt";
        try {
               ObjectInputStream ois = new ObjectInputStream(new FileInputStream(filename1));
               TableModel model = (TableModel)ois.readObject();
                jTable3.setModel(model);
               System.out.println("reading for " + filename1);
          }
          catch(Exception e) {
               System.out.println("Problem reading back table from file: " + filename1);
               return;
          } 

this is the objectoutput code

  private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
String filename1 = "studio1.txt";
         
          try {
              FileOutputStream fos = new FileOutputStream(new File(filename1));
              ObjectOutputStream oos = new ObjectOutputStream(fos);
               oos.writeObject(jTable2.getModel());
               oos.flush();
               oos.close();
               fos.close();
          }
          catch(IOException e) {
			System.out.println("Problem creating table file: " + e);
                        e.printStackTrace();
               return;
          }
          System.out.println("JTable correctly saved to file " + filename1);
}  

[Campbell Ritchie]

Welcome to JavaRanch

Please show us which line the Exception occurred on. Don't know whether the text file is necessary or not. Sorry.

You will need to find every object which might be invoked on that line, and check whether it is null, which is that much more difficult with all the additional code from NetBeans.

[roger lim shau xiong]

hi, thank you for reply me
i cant find the line of the exception code.


i had /*...*/ some of the code that generate from the GUI netbean at following

  /*
 * timetable.java
 *
 * Created on January 5, 2009, 8:49 PM
 */

package gui;
import java.io.*;
import java.util.Observable;
import java.util.Observer;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.TableModel;

public class timetables extends javax.swing.JFrame implements Observer, TableModelListener, Serializable{

   
    public timetables() {
        initComponents();
    }

    
    @SuppressWarnings("unchecked")
   
    private void initComponents() {

        jDialog1 = new javax.swing.JDialog();
        buttonGroup1 = new javax.swing.ButtonGroup();
        buttonGroup2 = new javax.swing.ButtonGroup();
        buttonGroup3 = new javax.swing.ButtonGroup();
        buttonGroup4 = new javax.swing.ButtonGroup();
        jTextField1 = new javax.swing.JTextField();
        jLayeredPane1 = new javax.swing.JLayeredPane();
        jLabel6 = new javax.swing.JLabel();
        jTabbedPane1 = new javax.swing.JTabbedPane();
        jScrollPane3 = new javax.swing.JScrollPane();
        jTable2 = new javax.swing.JTable();
        jScrollPane4 = new javax.swing.JScrollPane();
        jTable3 = new javax.swing.JTable();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
/*
       org.jdesktop.layout.GroupLayout jDialog1Layout = new org.jdesktop.layout.GroupLayout(jDialog1.getContentPane());
        jDialog1.getContentPane().setLayout(jDialog1Layout);
        jDialog1Layout.setHorizontalGroup(
            jDialog1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(0, 400, Short.MAX_VALUE)
        );
        jDialog1Layout.setVerticalGroup(
            jDialog1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(0, 300, Short.MAX_VALUE)
        );
*/
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

       
        jLayeredPane1.add(jLabel6, javax.swing.JLayeredPane.DEFAULT_LAYER);
        
        jTable2.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null},
                {null, null, null, null, null, null, null}
            },
            new String [] {
                "MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY", "SATURDAY", "SUNDAY"
            }
        ));
        
        
String filename1="studio1.txt";
        try {
               ObjectInputStream ois = new ObjectInputStream(new FileInputStream(filename1));
               TableModel model = (TableModel)ois.readObject();
                jTable3.setModel(model);
               System.out.println("reading for " + filename1);
          }
          catch(Exception e) {
               System.out.println("Problem reading back table from file: " + filename1);
               return;
          }
        
        jTable2.setRowHeight(20);
        jTable3.setRowHeight(20);
        
        jScrollPane3.setViewportView(jTable2);
        jScrollPane4.setViewportView(jTable3);
        jTable2.getColumnModel().getColumn(4).setResizable(false);
        jTable3.getColumnModel().getColumn(4).setResizable(false);
        jTabbedPane1.addTab("STUDIO 1", jScrollPane3);
        jTabbedPane1.addTab("STUDIO 2", jScrollPane4);
        jTextField1.setText("again n again");
        jLabel6.setText("jLabel5");
        jLabel6.setBounds(0, 0, -1, -1);
        jButton2.setText("jButton2");
        jButton1.setText("jButton1");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

/*             

        org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .add(jLayeredPane1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED, 66, Short.MAX_VALUE)
                .add(jTabbedPane1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 673, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                    .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                        .add(layout.createSequentialGroup()
                            .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                            .add(jTextField1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 160, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                            .addContainerGap(37, Short.MAX_VALUE))
                        .add(org.jdesktop.layout.GroupLayout.TRAILING, layout.createSequentialGroup()
                            .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                            .add(jButton1)
                            .add(56, 56, 56)))
                    .add(layout.createSequentialGroup()
                        .add(64, 64, 64)
                        .add(jButton2)
                        .addContainerGap())))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                    .add(org.jdesktop.layout.GroupLayout.TRAILING, layout.createSequentialGroup()
                        .add(jLayeredPane1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                        .add(131, 131, 131))
                    .add(layout.createSequentialGroup()
                        .add(164, 164, 164)
                        .add(jTextField1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)))
                .add(92, 92, 92)
                .add(jButton1)
                .add(41, 41, 41)
                .add(jButton2)
                .add(270, 270, 270))
            .add(org.jdesktop.layout.GroupLayout.TRAILING, layout.createSequentialGroup()
                .addContainerGap(23, Short.MAX_VALUE)
                .add(jTabbedPane1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 572, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                .add(37, 37, 37))
        );
*/
        pack();
        Object aaa=jTextField1.getText()+"sdfsdfsdfsdf";
        jTable2.setValueAt(aaa,4,2);
    }

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
String filename1 = "studio1.txt";
         
          try {
              FileOutputStream fos = new FileOutputStream(new File(filename1));
              ObjectOutputStream oos = new ObjectOutputStream(fos);
               oos.writeObject(jTable2.getModel());
               oos.flush();
               oos.close();
               fos.close();
          }
          catch(IOException e) {
			System.out.println("Problem creating table file: " + e);
                        e.printStackTrace();
               return;
          }
          System.out.println("JTable correctly saved to file " + filename1);
}



   
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new timetables().setVisible(true);
            }
        });
    }

    
    private javax.swing.ButtonGroup buttonGroup1;
    private javax.swing.ButtonGroup buttonGroup2;
    private javax.swing.ButtonGroup buttonGroup3;
    private javax.swing.ButtonGroup buttonGroup4;
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JDialog jDialog1;
    private javax.swing.JLabel jLabel6;
    private javax.swing.JLayeredPane jLayeredPane1;
    private javax.swing.JScrollPane jScrollPane3;
    private javax.swing.JScrollPane jScrollPane4;
    private javax.swing.JTabbedPane jTabbedPane1;
    private javax.swing.JTable jTable2;
    private javax.swing.JTable jTable3;
    private javax.swing.JTextField jTextField1;

    public void update(Observable o, Object arg) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public void tableChanged(TableModelEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }
   

}
  

[Bert Bates]

intermediate level question

[roger lim shau xiong]

did anyone know how to attach the .txt file?

[Campbell Ritchie]

Bert Bates wrote:intermediate level question

It wasn't originally. It was about finding a NullPointerException.

roger lim shau xiong:Why have you changed the original posting? It was about NullPointerExceptions yesterday, not NotSerializableExceptions. Why are you quoting different code from yesterday? If you change the original posting the replies will turn to nonsense.

Why are you passing so many nulls? Are you initialising all those references to real objects?

[roger lim shau xiong]

yes i had changed it because i had update the latest coding
i had change the code which i had show at the first msg
and i had change the subject because i found that the first line of the exception should be the java.io.NotSerializableException
and nullpointer exception had show at the bottom of NotSerializableException
and sorry for this, i won't change the original posting next time

the nulls is only the object that created by netbean
i had try to fill it full with object but the problem still the same
sorry again for the unconvenient

[roger lim shau xiong]

i had found a new thing that when i just double click the cell without change any data inside the table
and click the button "Save". the same exception which is
java.io.NotSerializableException: java.lang.reflect.Constructor
will come out again.

[Campbell Ritchie]

When you serialize an object, every field of every class must be a primitive or implement the Serializable interface or be labelled transient. So go through all your classes and look at all their types and see whether they all implement Serializable. Many well-known classes, eg String, ArrayList, already implement Serializable, so look at all the other classes.

[roger lim shau xiong]

i had create another class to serialize it

  package gui;


import java.io.Serializable;
import javax.swing.JTable;

public class Data implements Serializable {  
     public Data() {  
         model = new JTable();  
     }  
      
     private javax.swing.JTable model;  
 }  

and the outputstream i change to this

  data = new Data();
oos.writeObject(data);  

After this i click the save button
the java.io.NotSerializableException had been solve
but when i trying to read back the studio1.txt
it comes out another exception
Problem reading back table from file: studio1.txtjava.lang.ClassCastException: gui.Data

[roger lim shau xiong]

my problem had been solve since i create this class

 import java.io.Serializable;
public class Data implements Serializable {
        public Data() {  
        model = new javax.swing.table.DefaultTableModel(); 
        }  
      
        public javax.swing.table.DefaultTableModel model; 
 }   

but there is another problem after i save the table
after i save the table, i click the load button to load back,
the table just become empty ,its looks like load a empty object into the frame
can anybody help me with this problem?

i can save the JTable by this code

  jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                String filename1 = "studio1.txt";
                try {
                    FileOutputStream fos = new FileOutputStream(new File(filename1));
                    ObjectOutputStream oos = new ObjectOutputStream(fos);
                    oos.writeObject(data);
                    oos.flush();
                    oos.close();
                    fos.close();
                }
                catch(IOException e) {
                    e.printStackTrace();
                    return;
                }
                System.out.println("JTable correctly saved to file " + filename1);
                }
        });  

and i load the JTable by this code

  jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
              try{
                String filename1 = "studio1.txt";
                FileInputStream fis=new FileInputStream(filename1);
                ObjectInputStream ois = new ObjectInputStream(fis);
                data = (Data)ois.readObject();
                ois.close();
                fis.close();
                jTable2.setModel(data.model);
                jTable3.setModel((DefaultTableModel)data.model);
                System.out.println("reading for " + filename1);
             }
             catch(Exception e) {
               e.printStackTrace();
               return;
          }
                }
        });  

after this my table become empty..just like a empty frame.
anybody help will be my very appreciate