Adding a window to container error

Question

I have this table that I want to add to a my main program.
The table works but when I add the table module to the main program I get an error.
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: adding a window to a container
This is the table program
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
import java.io.*;
public class TableSave extends JFrame
     private JTable table;
     public TableSave()
          String[] columnNames = { "Depth", "Density"};
          Object[][] data =
          table = new JTable(data, columnNames)
               //  Returning the Class of each column will allow different
               //  renderers to be used based on Class
               public Class getColumnClass(int column)
                    return getValueAt(0, column).getClass();
          table.putClientProperty("terminateEditOnFocusLost", Boolean.TRUE);
          table.setPreferredScrollableViewportSize(table.getPreferredSize());
          JScrollPane scrollPane = new JScrollPane( table );
          getContentPane().add( scrollPane );
          //  Save table to file button.
          //  Actually the code only prints out the data,
          //  its up to you to modify the code to write it to a file
          JButton button2 = new JButton( "Save Table to File" );
          button2.addActionListener( new ActionListener()
              JFileChooser fc=new JFileChooser(System.getProperty("user.dir"));
                    //show dialog
               public void actionPerformed(ActionEvent e)
                    int rows = table.getRowCount();
                    int columns = table.getColumnCount();
                    //  Write out the Column Headers
                    TableColumnModel header = table.getColumnModel();
                    for (int k = 0; k < columns; k++)
                         TableColumn column = header.getColumn(k);
                         String value = (String)column.getHeaderValue();
                         //System.out.print( value );
                         //System.out.print( "|" );
                    //System.out.println();
                    //  Write out the table data
               try{
                    int fd = fc.showSaveDialog(TableSave.this);
                   if(fd==JFileChooser.APPROVE_OPTION){
                         FileOutputStream fo=new FileOutputStream(fc.getSelectedFile());
                         PrintStream ps=new PrintStream(fo);
                    for (int j = 0; j < rows; j++)
                         for (int k = 0; k < columns; k++)
                              Object value = table.getModel().getValueAt(j, k);
                              ps.println(value.toString() );
                              //System.out.print( value.toString() );
                              //System.out.print( "|" );
                      }//System.out.println();
                 }catch(Exception ex){}
          getContentPane().add(button2, BorderLayout.SOUTH);
     public static void main(String[] args)
          TableSave frame = new TableSave();
          frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
          frame.pack();
          frame.setVisible(true);
}then I add it to the main program as follows
public void actionPerformed (ActionEvent event)
        // Determine which object was the source of the event.
        Object source = event.getSource ();
      else if (source == menuSheet)
          count2++;
          JInternalFrame f = new JInternalFrame("mass/Density"+count2);
            f.setResizable(true);
          f.setClosable(true);
          f.setMaximizable(true);
          f.setIconifiable(true);
          f.setSize(270,420);
          f.setLocation(count2*15,count2*15);
          f.addInternalFrameListener(this);
          f.setVisible(true);
          frame.getContentPane().add(f);
            tablesave = new TableSave();
            Container pane = f.getContentPane ();
        pane.setLayout (new BorderLayout());
        pane.add (tablesave, BorderLayout.CENTER);
Help me resolve this or offer a solution to this problem.
regards,
moi

Answer 1

Hi there,
Both Internal Frames and Jframe are containers.
Jframe is a heavy weight component which you are trying to add in a lightweight internal Frame component, hence the error.
You try having the table implementation which is just a JTable and not a Jframe (You are currently extending from JFrame), then it will work out.
Cheers
Ravi Sinha