### Question:
MultipleAddresses { public boolean isEmpty() { return addresses.isEmpty(); } MultipleAddresses();  MultipleAddresses(Collection<InetSocketAddress> addresses);  MultipleAddresses(InetSocketAddress address);  MultipleAddresses(Collection<InetSocketAddress> addresses, Duration timeout); boolean isEmpty(); Set<InetSocketAddress> getAllAddresses(); Set<InetSocketAddress> getWildcardAddresses(); List<Integer> getAllPorts(); List<String> getAllHostStrings(); void addAddress(InetSocketAddress address); InetSocketAddress getReachableAddress(); Set<InetSocketAddress> getAllReachableAddresses(); Set<InetSocketAddress> getAllReachableAddressesOrAll(); InetSocketAddress getReachableOrOne(); void recreateSocketAddresses(); InetSocketAddress getOne(); int size(); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString(); static final Duration DEFAULT_TIMEOUT; }### Answer:
@Test public void testIsEmpty() { MultipleAddresses multipleAddresses = new MultipleAddresses(); assertTrue(multipleAddresses.isEmpty()); multipleAddresses.addAddress(new InetSocketAddress(22)); assertFalse(multipleAddresses.isEmpty()); }