Conexão com o banco de dados

import java.sql.*;

/**
 *
 * @author Diego e Rejane
 */
class BDConexao {

    private static Connection conexao = null;
    private String url, nomeBanco, urlDriver, ipMySQL, portaMySQL, usr, pwd;

    protected BDConexao(String ipMySQL, int portaMySQL, String usuario, String senha){
        this.ipMySQL = ipMySQL;
        this.portaMySQL = portaMySQL + "";
        this.usr = usuario;
        this.pwd = senha;
    }

    protected Connection abrirConexao(String nomeEsquema) {
		url = "jdbc:mysql://" + ipMySQL + ":" + portaMySQL + "/";
        this.nomeBanco = nomeEsquema;
        urlDriver = "com.mysql.jdbc.Driver";
        try {
			Class.forName(urlDriver).newInstance();
			conexao = DriverManager.getConnection(url + nomeEsquema, usr, pwd);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return conexao;
	}

	protected void fecharConexao() {
		try {
			conexao.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	protected Savepoint iniciarTransacao(String nome) {
		try {
			conexao.setAutoCommit(false);
			return conexao.setSavepoint(nome);
		} catch (SQLException e) {
			e.printStackTrace();
			return null;
		}
	}

	protected void finalizarTransacao() {
		try {
			conexao.commit();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	protected void cancelarTransacao(Savepoint sp) {
		try {
			conexao.rollback(sp);
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	protected void limpaTabela(String tab) {
		String sql = "DELETE FROM "+ tab;
		try {
			PreparedStatement ps = conexao.prepareStatement(sql);
			ps.executeUpdate();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Savepoint;
import java.sql.Statement;

/**
 *
 * @author Diego e Rejane
 */
public class BDManipulacao {

    private Connection conexao;
    private BDConexao metodos;
    private Statement stmt = null;

    public BDManipulacao(String ipMySQL, int portaMySQL, String usuario, String senha) {
        this.metodos = new BDConexao(ipMySQL, portaMySQL, usuario, senha);
        this.conexao = metodos.abrirConexao("teste");
}
//colocar as consultas, métodos, etc