Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at crudvilcun.GUI.btnBuscarActionPerformed(GUI.java:111)
    at crudvilcun.GUI.access$000(GUI.java:12)
    at crudvilcun.GUI$1.actionPerformed(GUI.java:54)

package crudvilcun;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

public class Metodos {

    public static final String driver = "com.mysql.jdbc.Driver";
    public static final String url = "jdbc:mysql//localhost:3306/tienda";
    public static final String username = "root";
    public static final String password = "";
    Connection con = null;
    ResultSet rs = null;
    PreparedStatement ps = null;
    GUI contenido;

    public Connection Conexion() {

        try {
            Class.forName(driver);
            con = (Connection) DriverManager.getConnection(url, username, password);

        } catch (ClassNotFoundException | SQLException e) {
            System.out.println("ERROR: " + e);
        }

        return con;
    }

    public void BuscarRegistro() {

        try {
            con = Conexion();
            ps = (PreparedStatement) con.prepareStatement("SELECT * FROM personas (nombre,rut,dirección) where nombre=(?)");
            rs = ps.executeQuery();

            if (rs.next()) {
                contenido.txtNombre.setText(rs.getString("nombre"));
                contenido.txtDireccion.setText(rs.getString("direccion"));
                contenido.txtRut.setText(rs.getString("rut"));

            }

        } catch (SQLException e) {
            System.out.println("ERROR: " + e);
        }
    }

}