Java Mysql connection

package rnb.cell;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
/**
 *
 * @author Azhar
 */
public class koneksi {
    private static Connection konek;
    public static Connection getkoneksi(){
        if (konek == null ){
        try{String url = "jdbc:mysql://localhost/gammu_db";
        String user = "root";
        String pass = "";
        DriverManager.registerDriver(new com.mysql.jdbc.Driver());
        konek = DriverManager.getConnection(url, user, pass);
        System.out.println("succses");}
        catch(SQLException t){
  

        System.out.println("Error in connection");}
        }
        return konek;
    }
   public void close() throws SQLException{
   konek.close();
   }
  
}
pastikan telah ada library mysql-connector-java-5.1.18-bin.jar  di folder lib