Erro: java.sql.SQLException: No suitable driver found for jdbc:mysql//localhost:3306/sistema

public class ConexaoFactory {
private static final String USUARIO = “root”;
private static final String SENHA = “84304837ifrn”;
private static final String URL = “jdbc:mysql//localhost:3306/sistema”;

public static Connection conectar() throws SQLException {
Class.forName("com.mysql.jdbc.Driver");
Connection conexao = DriverManager.getConnection(URL, USUARIO, SENHA);
return conexao;
}

public static void main(String[] args) throws ClassNotFoundException {
try {
    Connection conexao = ConexaoFactory.conectar();
    System.out.println(“Conectado com Sucesso!!”);
    }

    catch(SQLException ex) {
    	ex.printStackTrace();
    	System.out.println("Conexão Falhou!");
    }
    }

    }