Erro ao incluir no BD

Estou com o seguinte erro:

Exception in thread “main” java.lang.ClassCastException: net.sourceforge.jtds.jdbc.ConnectionJDBC3

at Teste.inclusao(Teste.java:17)

at Main.main(Main.java:10)

Java Result: 1

CONSTRUÍDO COM SUCESSO (tempo total: 0 segundos)

import java.sql.*;

public class ConectaBd {

  public Connection con = null;
  public Statement stm;
  private ResultSet resultado_RS;
  private static final String URL = "jdbc:jtds:sqlserver://PC/BDteste";
  private static final String DRIVER = "net.sourceforge.jtds.jdbc.Driver";
  private static final String USUARIO = "sa";
  private static final String SENHA = "123456";

  public static Connection getConnection() throws SQLException{
         try{
             Class.forName(DRIVER);
             System.out.println("Conectando a Banco de Dados...");
             return DriverManager.getConnection(URL, USUARIO, SENHA);

         }catch (ClassNotFoundException e) {
                     System.out.println("Failha ao caregar o drive");

             throw new SQLException (e.getMessage());
         }
     }

 public Connection desconectaBanco() {
  	try {
  	     con.close();
  	}
  	catch(Exception e) {
  		e.printStackTrace();
  	}
  	return con;
  }

}

import java.sql.SQLException;

public class Main {

    public static void main(String[] args) throws SQLException {

        Teste t = new Teste();
        t.inclusao();
    }

}

import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
import javax.swing.JOptionPane;

public class Teste {

    private String codigo, nome;
    private Statement stm = null;
    private ConectaBd conexao;

    @SuppressWarnings("static-access")
    public boolean inclusao() {
    try {
           ConectaBd con = new ConectaBd();
           con.getConnection();
           stm = (Statement) ConectaBd.getConnection();
           PreparedStatement pstmt = stm.getConnection().prepareStatement(
             "insert into tabTeste(codigo, nome) values (?, ?) ");
           pstmt.setInt(1, 1);
           pstmt.setString(2, "maria");
           pstmt.executeUpdate();
         } catch (SQLException ex) {
           JOptionPane.showMessageDialog(null, "Erro ao gravar", "Aviso do sistema", JOptionPane.INFORMATION_MESSAGE);
         }
      return true;
    }
}