JOptionPane.showMessageDialog(frame, "displayed");

                while (rs.next()) {
                    String name  = rs.getString("Name");
                    String size  = rs.getString("size");
                    String price  = rs.getString("price");
                    textArea_Name.append(name);
                    textArea_size.append(size);
                    textArea_price.append(price);
                    comboBox_1.addItem(rs.getString("Name"));
                    comboBox_1.getSelectedItem();

                }}


                 catch (SQLException e ) {
                    System.out.println("user not added");
                    e.printStackTrace();
                 }

            }
        });

con = DriverManager.getConnection("jdbc:mysql://:3306/database","user","password");
    stat = con.createStatement();
    ResultSet rs = stat.executeQuery("select name from student;");
    while(rs.next()){
        jComboBox1.addItem(rs.getString("name"));
        }
    rs.close();
    stat.close();
    con.close();

try {
             Statement stmt = db.con.createStatement();
        ResultSet rs = stmt5.executeQuery("select * from tbl_your_table");
        while (rs.next()) {
            String pat = rs.getString("name");
            jComboBox.addItem(pat);
        }

    } catch (Exception e) {

        JOptionPane.showMessageDialog(null, e);
    }

try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

Connection conn= DriverManager.getConnection("jdbc:odbc:driverName");
Statement st = conn.createStatement();

 ResultSet r=st.executeQuery("select * from tableName");

 while (r.next()) {

     JComboBox.addItem(r.getString("Key_Coloumn_Name"));
 }


    conn.close();
    } catch (Exception e) {
JOptionPane.showMessageDialog(null,"Failed to Connect to Database","Error Connection", JOptionPane.WARNING_MESSAGE);
System.exit(0);
}