save data

try {
            String sql = "INSERT INTO tbl_pinjaman VALUES ('"+txt_tgl.getText()+"','"+txt_nopin.getText()+"','"+cb_kel.getSelectedItem()+"','"+txt_nama.getText()+"','"+txt_simpanan.getText()+"','"+txt_jumlah.getText()+"','"+txt_waktu.getText()+"','"+txt_bunga.getText()+"')";
            java.sql.Connection conn=(Connection)config.configDB();
            java.sql.PreparedStatement pst=conn.prepareStatement(sql);
            pst.execute();
            JOptionPane.showMessageDialog(null, "Penyimpanan Data Berhasil");
             load_table();
        } catch (Exception e) {
            JOptionPane.showMessageDialog(this, e.getMessage());
        }