JTable: Custom Table Model (pI)

This is a follow-up to thread http://forum.java.sun.com/thread.jspa?threadID=725162 and thread http://forum.java.sun.com/thread.jspa?threadID=725158.
As I'm hoping to have a table of 5 columns, where the 4th and 5th columns are for integer and float data types respectively, I am creating a custom table model under the assumption that I will not know beforehand the number of rows the table will contain.
Problems? Having not specified the cell contents of the table, since it will be pupulated by users unknown to me, I did not declare or initialize a variable similar to TableDemo's data variable of type Object (see the TableDemo tutorial http://java.sun.com/docs/books/tutorial/uiswing/components/example-swing/TableDemo.java). As such, I am unable to specify the return parameters for the getRowCount() and getValueAt(~, ~) methods.
To overcome this, I sought to replicate the example shown in TableDemo by doing the following:
Object[][] cell = {"", "", "", new Integer(0), new Float(0.00f)};
public int getRowCount()
public Object getValueAt(int row, int column)
  return cell[row][column];
//...I got the following errors:
pathname\CustomTableModel.java:line #: incompatible types
found: java.lang.String
required: java.lang.Object[]
and the errors continue...
So I tried
Object[] cell = {"", "", "", new Integer(0), new Float(0.00f)};
// ...However, I got this error:
C:\...\CustomTableModel.java:line #:array required, but java.lang.String found
return cell[row][column];
.......................... ^
I just want to set the return parameters for getRowCount() and getValueAt(~,~) in the custom table model I'm creating. How do I do this?
PS Thanks for reading this far...

I decided to use the DefaultTableModel, after all. I was using it before, but at the time, i didn't know that certain things I wanted to accomplish, it could too.
Anyways, here's what I have been doing: http://forum.java.sun.com/thread.jspa?threadID=725861
Thanks nonetheless for your help. And by the way, my client is adamant that I use a LinkedList, rather than a Vector for this project. But nevertheless, thanks.

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      import java.awt.Frame;
      import java.awt.Menu;
      import java.awt.MenuBar;
      import java.awt.MenuItem;
      import java.awt.MenuShortcut;
      import java.awt.event.ActionEvent;
      import java.awt.event.ActionListener;
      import java.awt.event.KeyEvent; // for MenuItem shortcuts
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      import java.awt.event.WindowEvent;
      import java.awt.event.WindowListener;
      import javax.swing.JOptionPane;
      import javax.swing.JScrollPane; // JTable added to it, aiding flexibility
      import javax.swing.JTable; // The personally preferred GUI for this purpose
            // Provides a basic implementation of TableModel
      import javax.swing.table.DefaultTableModel;
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              // programmer will be using LinkedLists
      import java.util.LinkedList;
      // User-defined classes
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         String title = "",      // Frame's title
                file = "";           // pathname of the file to be opened
          // Declaring Menu and MenuItem variables
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         // recordM
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