title: Set value of jtable column using setValueAt()
body: <p>I am trying to set the value of a jtable column using setValueAt() in netbeans and it is not working.
  following is what i have set using 'customize code' option.
  The columns showing null are of type boolean ie they can be checked and unchecked.
  I want to read values from the database and set the column values accordingly.</p>
  
  <pre><code>pref_table = new javax.swing.JTable();
  
  pref_table.setModel(new javax.swing.table.DefaultTableModel(
  new Object [][] {
      {"MONDAY", null, null, null, null},
      {"TUESDAY", null, null, null, null},
      {"WEDNESDAY", null, null, null, null},
      {"THURSDAY", null, null, null, null},
      {"FRIDAY", null, null, null, null},
      {"SATURDAY", null, null, null, null}
  },
  new String [] {
      "DAY", "9 A.M-11 A.M", "11 A.M-1 P.M", "1 P.M-3 P.M", "3 P.M-5 P.M"
  }
  ) {
      Class[] types = new Class [] {
      java.lang.String.class, java.lang.Boolean.class, java.lang.Boolean.class, java.lang.Boolean.class, java.lang.Boolean.class
  };
  
  public Class getColumnClass(int columnIndex) {
      return types [columnIndex];
  }
  });
  </code></pre>
  
  <p>As the frame containing the jtable(pref_table) is initialised,the column values are either set to true or false by calling the following function but it does not seem to work.</p>
  
  <pre><code>public void set_tab_val(boolean x,int r,int c)
  {
    pref_table.setValueAt(true,r,c);
  }
  </code></pre>