Problema con un metodo static

[NcophFace]

L'altro giorno poi ho risolto unendo i due metodi in uno solo, in questo modo

public static Connection ConnectDb(){
        
    String url_database = "";
    String username = "";
    String password = "";
    
    Properties prop = new Properties();
               
        try {   
    		prop.load(new FileInputStream("config.properties"));
                
                url_database = prop.getProperty("Url");
                username = prop.getProperty("Username");
                password = prop.getProperty("Password");
                
    	} catch (IOException ex) {
    		ex.printStackTrace();
        }
                                                  
        
        try{         
            Class.forName ("com.mysql.jdbc.Driver");
            url_database = "jdbc:mysql://"+url_database;
            Connection conn = DriverManager.getConnection (url_database,username,password);
            
            return conn;
        }
        catch (Exception e) {
            JOptionPane.showMessageDialog(null, e);
            return null;
        }  
    }