NetUtils { public static boolean isMulticastAddress(String host) { int i = host.indexOf('.'); if (i > 0) { String prefix = host.substring(0, i); if (StringUtils.isInteger(prefix)) { int p = Integer.parseInt(prefix); return p >= 224 && p <= 239; } } return false; }  static int getRandomPort(); static int getAvailablePort(); static int getAvailablePort(int port); static boolean isInvalidPort(int port); static boolean isValidAddress(String address); static boolean isLocalHost(String host); static boolean isAnyHost(String host); static boolean isInvalidLocalHost(String host); static boolean isValidLocalHost(String host); static InetSocketAddress getLocalSocketAddress(String host, int port); static String getLocalHost(); static String filterLocalHost(String host); static String getIpByConfig(); static InetAddress getLocalAddress(); static boolean isPreferredNetworkInterface(NetworkInterface networkInterface); static NetworkInterface findNetworkInterface(); static String getHostName(String address); static String getIpByHost(String hostName); static String toAddressString(InetSocketAddress address); static InetSocketAddress toAddress(String address); static String toURL(String protocol, String host, int port, String path); static void joinMulticastGroup(MulticastSocket multicastSocket, InetAddress multicastAddress); static void setInterface(MulticastSocket multicastSocket, boolean preferIpv6); static boolean matchIpExpression(String pattern, String host, int port); static boolean matchIpRange(String pattern, String host, int port); static boolean isMulticastAddress(String host);  }
@Test public void testIsMulticastAddress() { assertTrue(NetUtils.isMulticastAddress("224.0.0.1")); assertFalse(NetUtils.isMulticastAddress("127.0.0.1")); }