CaselessUnmodifiableMultivaluedMap extends CaselessMultivaluedMap<T> { @Override public List<T> getList(String key) { return Collections.unmodifiableList(super.getList(key)); } CaselessUnmodifiableMultivaluedMap();  CaselessUnmodifiableMultivaluedMap(int capacity);  CaselessUnmodifiableMultivaluedMap(Map<String, List<T>> m); @Override void add(String key, T value); @Override void clear(); @Override Set<Entry<String, List<T>>> entrySet(); @Override List<T> get(Object key); @Override List<T> getList(String key); @Override Set<String> keySet(); @Override List<T> put(String key, List<T> value); @Override void putAll(Map<? extends String, ? extends List<T>> m); @Override void putSingle(String key, T value); @Override List<T> remove(Object key); @Override void addAll(String key, T... newValues); @Override void addAll(String key, List<T> valueList); @Override void addFirst(String key, T value); @Override Collection<List<T>> values();  }
@Test public void testGetList() { assertEquals(Arrays.asList("a", "b"), map.getList("k")); List<String> list = map.getList("x"); assertNotNull(list); assertEquals(0, list.size()); }