private void jButton1ActionPerformed(
      java.awt.event.ActionEvent evt) { // GEN-FIRST:event_jButton1ActionPerformed
    // TODO add your handling code here:
    if (t1.getText().equals("")
        || t2.getText().equals("")
        || t3.getText().equals("")
        || t4.getText().equals("")) {
      err = new Error();
      err.setMsg("Faltan datos por ingresar");
      err.setVisible(true);
    } else {
      // "INSERT INTO Alumnos (cod_alum, grupo) VALUES ('1', '1');"
      String cad =
          "VALUES ('"
              + lblid.getText()
              + "','"
              + t1.getText()
              + "','"
              + t2.getText()
              + "','"
              + t3.getText()
              + "',+'"
              + t4.getText()
              + "');";
      conexion("INSERT INTO clientes (Id, nombre, fecha, direccion, telefono) " + cad);

      try {
        conn.close();
        if (adm != null) {
          conn.close();
          adm.update();
        }
      } catch (SQLException ex) {
        Logger.getLogger(nuevocliente.class.getName()).log(Level.SEVERE, null, ex);
      }
      if (u != null) {
        u.setVisible(true);
      }
      int x = Integer.parseInt(lblid.getText());
      x++;
      lblid.setText("" + x);
      t1.setText("");
      t2.setText("");
      t3.setText("");
      t4.setText("");
      this.dispose();
    }
  } // GEN-LAST:event_jButton1ActionPerformed