FakturaSerializer serializer = new FakturaSerializer();
Faktura invoice = serializer.fromFile(new File("src/test/resources/fa.xml"), true);

FakturaSerializer fakturaSerializer = new FakturaSerializer();

Faktura invoice = fakturaSerializer.create();

Faktura.Podmiot1 podmiot1 = new Faktura.Podmiot1();
TAdres address = new TAdres();
address.setAdresL1("ul. Kolejowa 123");
address.setAdresL2("05-092 Łomianki");

podmiot1.setAdres(address);
invoice.setPodmiot1(podmiot1);

val str = fakturaSerializer.toString(invoice, false);

System.out.println(str);

val errors = new LinkedList<SAXParseException>();
val features = Set.of(new XMLValidator.SchemaFactoryFeature(XMLConstants.FEATURE_SECURE_PROCESSING, false));
// We need disable secure processing because the schema has restrictions to more than 1000 elements in a sequence
// which is completely ridiculous, but what we can do...

URL url = new URL("https://crd.gov.pl/wzor/2023/06/29/12648/schemat.xsd");
val schema = new StreamSource(url.openStream());
val result = XMLValidator.validate(new FileReader("src/test/resources/fa.xml"), schema, errors, features);