Path of properties file in java

I have a property file which is inside a default package and the class in which I am using the properties file is also in the same default package. If I use just the file name without any path I am getting error. Obviously that is not correct as I should give some kind of path to refer to tat file. I will build the application make it as a jar file so how should I give the path as the properties file should go inside that jar file. I am using Netbeans IDE.

EDIT

 Properties pro = new Properties();

    try {            
        pro.load(new FileInputStream("pos_config.properties"));
        pro.setProperty("pos_id", "2");
        pro.setProperty("shop_type", "2");
        pro.store(new FileOutputStream("pos_config.properties"), null);
        String pos_id = pro.getProperty("pos_id");
        if(pos_id.equals("")){
           pos_id="0" ;
        }
        global_variables.station_id = Integer.parseInt(pos_id);
        String shop_type = pro.getProperty("shop_type");
        if(shop_type.equals("")){
           shop_type="0" ;
        }
        global_variables.shop_type = Integer.parseInt(shop_type);
    } catch (IOException ex) {
        Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
    }