Thread: Problem with parsing XML file for the first time

I'm parsing an XML file for the first time for an homework I have. I am having a problem that is probably something stupid but I can't find what is going wrong. Some pieces are in French as that's my main language.

Here's the piece of codes that I am having troubles with.
So with those last lines of code, I am able to print the informations I need to send to my constructor.

public void ParseXML(File fichierXML){
 
        final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
 
        {
            try {
                final DocumentBuilder builder = factory.newDocumentBuilder();
                final Document document = builder.parse(fichierXML);
                final Element racine = document.getDocumentElement();
                final NodeList racineNoeuds = racine.getChildNodes();
                final int nbRacineNoeuds = racineNoeuds.getLength();
 
                // Ajustement du fichier XML
                document.getDocumentElement().normalize();
 
                // Affichage du noeud principal
                System.out.println("Racine : " + racine.getNodeName());
 
                for (int i = 0; i<nbRacineNoeuds; i++)
                {
                    if(racineNoeuds.item(i).getNodeType() == Node.ELEMENT_NODE)
                    {
                        final Element sousSection = (Element) racineNoeuds.item(i);
                        System.out.println("Sous-section : " + sousSection.getNodeName());
 
                        final NodeList usines = sousSection.getElementsByTagName("usine");
                        final int nbUsinesElements = usines.getLength();
 
                        for(int j = 0; j<nbUsinesElements; j++) {
 
                            final Element usine = (Element) usines.item(j);
                            String type = usine.getAttribute("type");
                            System.out.println(usine.getAttribute("type"));
                            String StringId = usine.getAttribute("id");
                            System.out.println(usine.getAttribute("id"));
                            String StringX = usine.getAttribute("x");
                            System.out.println(usine.getAttribute("x"));
                            String StringY = usine.getAttribute("y");
                            System.out.println(usine.getAttribute("y"));
 
                            //int id = Integer.parseInt(StringId);
                            //int x = Integer.parseInt(StringX);
                            //int y = Integer.parseInt(StringY);
 
                            //AjouterBatiment(new Usine(1, ImageIO.read(new File(("src/ressources/UMP0%.png"))),
                            //        new Point(x,y), 100));
                        }
                    }
                }
 
            } catch (ParserConfigurationException | IOException | SAXException |  NumberFormatException e) {
                e.printStackTrace();
            }
 
        }
 
    }

Now, whenever I remove the comments from the lines where I try to assign those to a String variable, if I check the debugger, I can see that they are empty. I do not understand why because they just printed out one line before.

So then obviously I am having an error after that when I try to convert the String I get into an int because the variable is empty.

Here is the XML file : https://pastebin.com/GyxZ42a5
Here is the full class : https://pastebin.com/sXGAD85s

Any help would be very appreciated as I am working on this particular problem since last night without much luck.

Thank you!

Can you post all the code needed to compile and execute it? There needs to be import statements and a class definition and a main method that starts the execution of the method.

I am having an error

Please copy the full text of the error message and paste it here. It has important info about the error.

The code does not compile because of missing classes.
Please remove all classes that are not needed for testing. The code for testing should have the minimum needed to compile, execute and show the problem.
Also there is no main method.

I am getting is a java.lang.NumberFormatException: For input string: ""

What source line is that on? Why do you think the String variable should have a numeric value?