public static int getFactoryId(String prop, int defaultId) {
        final String value = System.getProperty(prop);
        if (value != null) {
            try {
                return Integer.parseInt(value);
            } catch (NumberFormatException e) {
                Logger.getLogger(FactoryIdHelper.class).finest("Parameter for property prop could not be parsed", e);
            }
        }
        return defaultId;
    }
@Test
    public void testPropWithValidNumber() throws Exception {
        String key = "hazelcast.test.prop";
        System.setProperty(key, "1");
        int factoryId = FactoryIdHelper.getFactoryId(key, 10);

        assertEquals(1, factoryId);

        assertUtilityConstructor(FactoryIdHelper.class);
    }