### Question:
NetUtils { public static int getAvailablePort() { ServerSocket ss = null; try { ss = new ServerSocket(); ss.bind(null); return ss.getLocalPort(); } catch (IOException e) { return getRandomPort(); } finally { if (ss != null) { try { ss.close(); } catch (IOException e) { } } } }  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 InetAddress getLocalAddress(); 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);  }### Answer:
@Test public void testGetAvailablePort() throws Exception { assertThat(NetUtils.getAvailablePort(), greaterThan(0)); assertThat(NetUtils.getAvailablePort(12345), greaterThanOrEqualTo(12345)); assertThat(NetUtils.getAvailablePort(-1), greaterThanOrEqualTo(30000)); }