Java: remove columns in a JTable

Hello experts,
in my java application I use the following routine.
The routine works fine if no of columns = zero.
---
    public void iniTable(String tableName, int [] mylength, String [] columnNames, String tableId, String mi_id,Vector data)
    {
      if(mylength==null||mylength.length==0)
      {
        mylength=new int[columnNames.length];
        for(int j=0;j<columnNames.length;j++)
          mylength[j]=150;
      }
      TableModel model = new TableModel(tableName,columnNames,tableId,data);
      model.setMitarbeiterID(mi_id);
      model.getData();
      setModel(model);
      _sorter = new SorterModel(model);
      JTable1.setModel(_sorter);

      //             here I'm going to check if there already columns exist
        int iColumnCount = JTable1.getColumnCount();
        if (iColumnCount == 0)
        {
        } else {
          // delete all existing columns
          JTable1.removeColumnSelectionInterval(0,iColumnCount-1);
        }
      //

      if (JTable1.getColumnCount() == 0)
      {
          for(int i = 0; i<mylength.length; i++)
          {
              TableColumn column = new TableColumn(i,mylength[i]);
              JTable1.addColumn(column);
          }
          _sorter.addMouseListenerToHeaderInTable(JTable1);
      }
    }
---
My target is, to check for the existing number of columns and remove all.
So, I can add all columns newly.
But it doesn't work.

  If anyone can help me
  please supply your ideas.

    Thank you for any help.


   HStrix