public static long currentTimeMillis() {
        // When an exception occurs in the Ticker mechanism, fall back.
        if (isFallback) {
            return System.currentTimeMillis();
        }

        if (!isTickerAlive) {
            try {
                startTicker();
            } catch (Exception e) {
                isFallback = true;
            }
        }
        return currentTimeMillis;
    }
@Test
    void testCurrentTimeMillis() {
        assertTrue(0 < TimeUtils.currentTimeMillis());
    }