public static synchronized boolean isEmpty() {
        return CpeEcosystemCache.cache.isEmpty();
    }
@Test
    public void testIsEmpty() {
        Map<Pair<String, String>, String> map = new HashMap<>();
        CpeEcosystemCache.setCache(map);
        boolean expResult = true;
        boolean result = CpeEcosystemCache.isEmpty();
        assertEquals(expResult, result);
        map.put(new Pair<>("apache", "zookeeper"), "MULTPILE");
        expResult = false;
        result = CpeEcosystemCache.isEmpty();
        assertEquals(expResult, result);
    }