Error creating an object and calling a method, error: cannot find symbol

Question

I don't understand what I'm doing wrong, I have just one class then I created an object and I'm trying to call a method as follows:

• 117 DBgui gui=new DBguie();
• 118 gui.mostrarMarco();
• error: cannot find symbol c:\\users... line 118

I'm calling this method in main

import java.sql.*;
import java.awt.*;
import java.awt.event.*;

public class DBgui /*extends WindowAdapter implements ActionListener*/{
    Frame f_principal, f_vertabla, f_modificar, f_mostrartablas, f_creartabla, f_borrar;//contenedor
    Button b_aceptar, b_cancelar;//componentes
    Label label_nombre, label_atributo;
    TextField tf_nombre, tf_atributo;
    MenuBar mb; //barra para menus
    Menu m_mostrar, m_crear, m_vertabla, m_modificar, m_borrar;
    MenuItem mi_tablas, mi_tabla, mi_mostrardbs, mi_creardbs;

public DBgui() {
    //MARCOS
    f_principal=new Frame("Interfaz gráfica Base de datos");
    f_creartabla=new Frame("Crear Tabla");
    f_vertabla=new Frame("Ver Tabla");
    f_modificar=new Frame("Modificar Registro");
    f_borrar=new Frame("Borrar Registro");

    //BOTONES
    b_aceptar=new Button("Aceptar");
    b_cancelar=new Button("Cancelar");

    //ETIQUETAS
    label_nombre=new Label("Nombre");
    label_atributo=new Label("Atributos");

    //CAMPO DE TEXTO
    tf_nombre=new TextField();
    tf_atributo=new TextField();

    //MENU
    mb=new MenuBar();
    m_mostrar=new Menu("Mostrar");
    m_crear=new Menu("Crear");
    m_vertabla=new Menu("Ver Tabla");
    m_modificar=new Menu("Modificar");
    m_borrar=new Menu("Borrar");

    mi_tablas=new MenuItem("Mostrar Tablas");
    mi_tabla=new MenuItem("Crear Tabla");
    mi_creardbs=new MenuItem("Crear Base de datos");
    mi_mostrardbs=new MenuItem("Mostrar base de datos");
}

public void mostarMarco(){
    f_principal.setSize(800,600);

    //SE CONSTRUYE EL MENU
    f_principal.setMenuBar(mb);
    mb.add(m_mostrar);
    mb.add(m_crear);
    mb.add(m_vertabla);
    mb.add(m_modificar);
    mb.add(m_borrar);

    m_mostrar.add(mi_mostrardbs);
    m_mostrar.add(mi_tablas);
    m_crear.add(mi_creardbs);
    m_crear.add(mi_tabla);
    f_principal.setVisible(true);

    //OREJAS

}

public static Connection database(String database, String username, String password) {

Connection conn;
conn=null;
String url = "jdbc:mysql://localhost:3306/" + database;

//LOAD DRIVER
try {
    Class.forName("com.mysql.jdbc.Driver");
} 
catch (ClassNotFoundException e){
    System.err.println("Could not load database driver!");
}


//CONNECT TO DATABASE
try {
    conn = DriverManager.getConnection(url, username, password);
    return conn;
} catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}
return null;            
}

public static void mostrarTablas(Connection db) throws Exception{
    Statement stmt=db.createStatement();
    String sqlshowtables = "SHOW TABLES";
    ResultSet sst_ResultSet = stmt.executeQuery(sqlshowtables);
    while (sst_ResultSet.next()) {
      System.out.println(sst_ResultSet.getString(1));
    }
    db.close();
}

public static void main(String[] args) throws Exception{
    Connection db;
    db=database("testdb","root","chino130284");
    mostrarTablas(db);
    DBgui gui=new DBgui();
    gui.mostrarMarco();

}

}

It was something really really stupid, I was misspelling, I'm really embarrassed

Answer 1

There's an extra 'r' in your call. 'mostrar' vs 'mostar'.

Get a decent IDE so it will find these problems for you.

(EDIT: that was a little abrupt, and I apologize. Seriously though a modern IDE has far more features than the simple text editors of yesterday. I pasted your code into my IDE -- thank you for a complete example -- and used the auto-completion feature to find the correct method name. It's fast and easy and frankly makes me three to five times more productive at coding.)

   public static void main( String[] args )
           throws Exception
   {
      Connection db;
      db = database( "testdb", "root", "chino130284" );
      mostrarTablas( db );
      DBgui gui = new DBgui();
      gui.mostrarMarco();  // <-- extra 'r'
      gui.mostarMarco();

   }