private static EntityManagerFactory getEntityManagerFactory() {
        if (entityManagerFactory == null) {
            InputStream propertiesStream = null;
            try {
                propertiesStream = new FileInputStream(ContextParams.getDbPropertiesFile());
                final Properties properties = new Properties();
                properties.load(propertiesStream);
                entityManagerFactory = Persistence.createEntityManagerFactory("JURE_PU", properties);
            } catch (Exception exception) {
                LOGGER.error("Could not load DB properties. " + exception);
                throw new ExceptionInInitializerError(exception);
            } finally {
                try {
                    if (propertiesStream != null) {
                        propertiesStream.close();
                    }
                } catch (IOException exception) {
                    LOGGER.error("Could not close DB properties stream. " + exception);
                }
            }
        }