### Question:
ClientUtils { public static List<InetSocketAddress> parseAndValidateAddresses(List<String> urls) { List<InetSocketAddress> addresses = new ArrayList<>(); for (String url : urls) { if (url != null && !url.isEmpty()) { try { String host = getHost(url); Integer port = getPort(url); if (host == null || port == null) throw new ConfigException("Invalid url in " + CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG + ": " + url); InetSocketAddress address = new InetSocketAddress(host, port); if (address.isUnresolved()) { log.warn("Removing server {} from {} as DNS resolution failed for {}", url, CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG, host); } else { addresses.add(address); } } catch (IllegalArgumentException e) { throw new ConfigException("Invalid port in " + CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG + ": " + url); } } } if (addresses.isEmpty()) throw new ConfigException("No resolvable bootstrap urls given in " + CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG); return addresses; }  static List<InetSocketAddress> parseAndValidateAddresses(List<String> urls); static void closeQuietly(Closeable c, String name, AtomicReference<Throwable> firstException); static ChannelBuilder createChannelBuilder(AbstractConfig config);  }### Answer:
@Test public void testParseAndValidateAddresses() { check("127.0.0.1:8000"); check("mydomain.com:8080"); check("[::1]:8000"); check("[2001:db8:85a3:8d3:1319:8a2e:370:7348]:1234", "mydomain.com:10000"); List<InetSocketAddress> validatedAddresses = check("some.invalid.hostname.foo.bar.local:9999", "mydomain.com:10000"); assertEquals(1, validatedAddresses.size()); InetSocketAddress onlyAddress = validatedAddresses.get(0); assertEquals("mydomain.com", onlyAddress.getHostName()); assertEquals(10000, onlyAddress.getPort()); }