started getting Class Not Found Exception randomly

@Service
public class XmlParserUtil {
    private StatementDocumentWrapper convertToV053s02(InputStream is) throws JAXBException {
        JAXBContext jaxbContext = JAXBContext.newInstance(ObjectFactory.class);
        Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
        Document doc = ((JAXBElement<Document>) jaxbUnmarshaller.unmarshal(is)).getValue();
        StatementDocumentWrapper sDoc = new StatementV053S02DocumentWrapper(doc);
        return sDoc;
    }
    private StatementDocumentWrapper convertToV052s02(InputStream is) throws JAXBException {
        JAXBContext jaxbContext = JAXBContext.newInstance(lt.mycompany.iso20022.camt.v052s02.ObjectFactory.class);
        Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
        lt.mycompany.iso20022.camt.v052s02.Document doc = ((JAXBElement<lt.mycompany.iso20022.camt.v052s02.Document>) jaxbUnmarshaller.unmarshal(is)).getValue();
        StatementDocumentWrapper sDoc = new StatementV052S02DocumentWrapper(doc);
        return sDoc;
    }
    public StatementDocumentWrapper InputStreamToDocument(InputStream is) throws JAXBException, IOException {
        byte[] bytes = is.readAllBytes();
        StatementDocumentWrapper sd;
        try {
            sd = convertToV053s02(new ByteArrayInputStream(bytes));
        } catch (UnmarshalException e) {
            sd = convertToV052s02(new ByteArrayInputStream(bytes));
        }
        return sd;
    }
}