mysql - get more rows in JTable java -

i coded auto suggesting combo boxes. functionality is,

*when user type first letter in either combo box , data retrieves mysql database , show in popup list, when user click on suggested item ,then press add button item added j table , clears combo boxes

but when select item combo box , click add button before added 1 disappears

*how can keep both or many items in j table according above situation *

i'll post code:

private void namecomboactionperformed(java.awt.event.actionevent evt) {                                               string drugname = (string) namecombo.getselecteditem();     try{      string name = "select * druginfo itemname '"+drugname+"%'";      preparedstatement pstmt = conn.preparestatement(name);     resultset rs = pstmt.executequery();      while (rs.next()){         idcombo.setselecteditem(rs.getstring("itemid"));       }      }catch(exception e){       joptionpane.showmessagedialog(null,"error "+ e);     }    }                                           private void idcomboactionperformed(java.awt.event.actionevent evt) {                                             string drugid = (string) idcombo.getselecteditem();     try{      string name = "select * druginfo itemid '"+drugid+"%'";      preparedstatement pstmt = conn.preparestatement(name);     resultset rs = pstmt.executequery();      while (rs.next()){         namecombo.setselecteditem(rs.getstring("itemname"));       }      }catch(exception e){       joptionpane.showmessagedialog(null,"error "+ e);     }     try{      string exp = "select expdate druginfo itemid '"+drugid+"%'";     preparedstatement pstmt = conn.preparestatement(exp);     resultset rs2 = pstmt.executequery();      while (rs2.next()){         string date = rs2.getstring("expdate");          exptxt.settext(date);     }      }catch(exception e){       joptionpane.showmessagedialog(null,"error "+ e);     } }  

add button action performed adding item jtable;

private void add_btnactionperformed(java.awt.event.actionevent evt) {                                                  string temp = (string) idcombo.getselecteditem();         string sql = "select itemid,itemname,costprice,instock druginfo itemid=?";     try {            pst=conn.preparestatement(sql);         pst.setstring(1, temp);         rs=pst.executequery();         tablesale.setmodel(dbutils.resultsettotablemodel(rs));         idcombo.setselecteditem(null);         namecombo.setselecteditem(null);     } catch (exception ex) {        joptionpane.showmessagedialog(null, ex);     } 

add current selection(resultset data) jtable object without replacing old data.

rs=pst.executequery(); adddatatotable(tablesale,dbutils.resultsettotablemodel(rs)); idcombo.setselecteditem(null); namecombo.setselecteditem(null);  //add method public void adddatatotable(jtable table,tablemodel model) {     defaulttablemodel tablemodel = (defaulttablemodel) table.getmodel();     defaulttablemodel resultsetmodel = (defaulttablemodel) model;     (int = 0; < resultsetmodel.getrowcount(); i++) {         vector row=new vector();         (int j = 0; j < resultsetmodel.getcolumncount(); j++) {             row.addelement(resultsetmodel.getvalueat(i, j));         }         tablemodel.addrow(row);     }     tablemodel.firetabledatachanged(); }