### Question:
AbstractRegistry implements Registry { public List<URL> getCacheUrls(URL url) { for (Map.Entry<Object, Object> entry : properties.entrySet()) { String key = (String) entry.getKey(); String value = (String) entry.getValue(); if (key != null && key.length() > 0 && key.equals(url.getServiceKey()) && (Character.isLetter(key.charAt(0)) || key.charAt(0) == '_') && value != null && value.length() > 0) { String[] arr = value.trim().split(URL_SPLIT); List<URL> urls = new ArrayList<URL>(); for (String u : arr) { urls.add(URL.valueOf(u)); } return urls; } } return null; } AbstractRegistry(URL url); @Override URL getUrl(); Set<URL> getRegistered(); Map<URL, Set<NotifyListener>> getSubscribed(); Map<URL, Map<String, List<URL>>> getNotified(); File getCacheFile(); Properties getCacheProperties(); AtomicLong getLastCacheChanged(); void doSaveProperties(long version); List<URL> getCacheUrls(URL url); @Override List<URL> lookup(URL url); @Override void register(URL url); @Override void unregister(URL url); @Override void subscribe(URL url, NotifyListener listener); @Override void unsubscribe(URL url, NotifyListener listener); @Override void destroy(); @Override String toString();  }### Answer:
@Test public void getCacheUrlsTest() { List<URL> urls = new ArrayList<>(); urls.add(testUrl); Assertions.assertFalse(notifySuccess); abstractRegistry.notify(testUrl, listener, urls); Assertions.assertTrue(notifySuccess); List<URL> cacheUrl = abstractRegistry.getCacheUrls(testUrl); Assertions.assertTrue(cacheUrl.size() == 1); URL nullUrl = URL.valueOf("http: cacheUrl = abstractRegistry.getCacheUrls(nullUrl); Assertions.assertTrue(Objects.isNull(cacheUrl)); }