JTable with checkbox issue-Table is not created at runtime

Question

can anyone please help me. I am trying to create a dynamic table with checkboxes. Data are accessed from database. But it is not creating the table at runtime. It retrieves data from database properly. But I am not getting why it is not creating the table in a specified Panel (panTable). Below is the code:

int tasktotr=0;
Object[][] taskcells;
JTable ttable;

public void BuildTable() {
   Statement st;
   ResultSet rs;

   panTable.updateUI();
   String query="";
   try{
       Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
       conn=DriverManager.getConnection("jdbc:odbc:dsndbPMA","","");
       st=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
       query="select * from Task";
       rs=st.executeQuery(query);
       rs.last();
       tasktotr=rs.getRow();
       System.out.println("tasktotr="+tasktotr);
       taskcells=new Object[tasktotr][6];
       if(tasktotr>0){
           int cnt=0;
           rs.beforeFirst();
           for(int c=0;c<6;c++){
               if(c==cnt){
                   int r=0;
                   while(rs.next()){
                       if(c==0)
                           taskcells[r][c]=Boolean.FALSE;
                       else if(c==1)
                           taskcells[r][c]=rs.getString("Priority");
                       else if(c==2)
                           taskcells[r][c]=rs.getString("Subject");
                       else if(c==3)
                           taskcells[r][c]=rs.getString("Status");
                       else if(c==4)
                           taskcells[r][c]=rs.getString("DueDate");
                       else if(c==5)
                           taskcells[r][c]=rs.getString("%Complete");
                       else if(c==6)
                           taskcells[r][c]=rs.getString("Category");
                       r++;
                   }
               }
                rs.beforeFirst();
                cnt++;
           }
           rs.close();
           st.close();
           for(int i=0;i<tasktotr;i++){
               for(int j=0;j<6;j++){
                   System.out.println(taskcells[i][j]);
               }
           }
           TableModel tasktable=new TaskTableModel(tasktotr,7);
           ttable=new JTable(tasktable);

           TableColumnModel columnModel=ttable.getColumnModel();
           TableColumn column;
           for(int i=0;i<ttable.getColumnCount();i++) {
               column = columnModel.getColumn(i);
               if(i==0)
                   column.setPreferredWidth(40);
               if(i==1)
                   column.setPreferredWidth(40);
               if(i==2)
                   column.setPreferredWidth(150);
           }
           ttable.setRowHeight(18);
           ttable.setAutoResizeMode(ttable.AUTO_RESIZE_OFF);
           ttable.getTableHeader().setReorderingAllowed(false);

           JScrollPane scroll=new JScrollPane(ttable);
           scroll.setAutoscrolls(true);
           panTable.add(scroll);
           panTable.updateUI();
           panTable.revalidate();
       }
   }catch(Exception e){
       e.printStackTrace();
       JOptionPane.showMessageDialog(null,e.getMessage(),"Error!!",1);
   }
}


class TaskTableModel extends AbstractTableModel{
    int totrow,totcol;
    public TaskTableModel(int r,int c){
        totrow=r;
        totcol=c;
    }
    @Override
    public int getRowCount() {
        return totrow;
    }
    @Override
    public int getColumnCount() {
        return totcol;
    }

    public Object getValueAt(int r,int c) {
        return taskcells[r][c];
    }

    public String getColumnName(int c){
        if(c==0)
            return "Icon";
        else if(c==1)
            return "Priority";
        else if(c==2)
            return "Subject";
        else if(c==3)
            return "Status";
        else if(c==4)
            return "Due Date";
        else if(c==5)
            return "% Completed";
        else if(c==6)
            return "Category";
        else
            return "";
    }

    public void setValueAt(Object obj,int r,int c){

        taskcells[r][c]=obj;
        fireTableCellUpdated(r, c);
    }

    //Edit only first column.
    public boolean isCellEditable(int r,int c){
        return c==0;
    }

    //used to display checkbox else it will show true/false text instead of checkbox. n
    public Class getColumnClass(int c) {
        return getValueAt(0, c).getClass();
    }

}

Answer 1

The reason why it isn't displayed correctly is an ArrayIndexOutOfBoundsException within your getValueAt method. The table taskcells is created with six columns (also only six are filled and displayed in your print loop) but the table model is created with seven columns. If your correct it your code should work (although there might still be an issue within a code part you didn't post here).

Note: You may consider reading the data not column-wise but row-wise from the database, i.e. rearrange the rs and c loops. Then you can even omit the c-loop completely.