Table doesnt exist

Question

im trying to retrieve values from database and plot a graph. I downloaded jfreechart and invoke a method frm there. its a program where user choose an item from drop down list, this item is actually the tables from my database, and a textbox where they enter a pattern and it will search through from the table they selected from the combobox.
when i run this program, i get an error saying table or view does not exists. anyone can help me detect the error?
this is what ive done. this is the chart program
public barchart()
          MyBarsTest t = new MyBarsTest("test bars");
          ana.display();
            String sql = "SELECT Occurrence, megabasepairs FROM ChromosomeY where patterns ='" + pattern + "'";
         XYSeries series = new XYSeries("");
         try {
             conn = db.getConnection();
             Statement stat = conn.createStatement();
             rs = stat.executeQuery(sql);
             while (rs.next()) {
               series.add(rs.getInt("megabasepairs"), rs.getInt("Occurrence"));
           } catch (SQLException sqle) {
             sqle.printStackTrace();
         IntervalXYDataset mydataset= new XYSeriesCollection(series);
         JFreeChart chart =
          ChartFactory.createHistogram("Pattern Chart", 
             "Mbp","No. of  Patterns found",mydataset,PlotOrientation.VERTICAL,
             false,
             false,
             true                // Show legend
          ChartPanel panel = new ChartPanel(chart);
          panel.setPreferredSize(new Dimension(600, 400));
          t.setContentPane(panel);
          t.setSize(800, 600);
          t.setVisible(true);
     public static void main(String[] args)
          barchart bc = new barchart();
          bc.show();
     }this is the display method from the interface class to retrieve it.
public void display() {
          database db = new database();
          Vector occur = db.getOccur((String) chromBox.getSelectedItem(),pattTf.getText());
          Vector mega = db.getMBP((String) chromBox.getSelectedItem(),pattTf.getText());
          System.out.println();
          for (int i=0; i<occur.size(); i++)
               String mbp = (String) mega.elementAt(i);
               String occurrence = (String) occur.elementAt(i);
               System.out.println(occurrence + "\t" + mbp);
               resultTa.setText(occurrence + "\t" + mbp);
     }

Answer 1

ok... that line suppose to be this way, coz users have to choose ..
String sql = "SELECT Occurrence, megabasepairs FROM " + table + " where patterns ='" + pattern + "'";i have my ChromosomeY table in my database. But i don't know why it cant read. Maybe something to do with retrieving it ?