### Question:
B2Collections { public static <K,V> Map<K,V> unmodifiableMap(Map<K,V> orig) { final Map<K,V> map = new TreeMap<>(); map.putAll(orig); return Collections.unmodifiableMap(map); }  static Set<T> unmodifiableSet(T[] elements); static Map<K,V> unmodifiableMap(Map<K,V> orig); static Map<K, V> mapOf(); static Map<K, V> mapOf(K k1, V v1); static Map<K, V> mapOf(K k1, V v1,
                                        K k2, V v2); static Map<K, V> mapOf(K k1, V v1,
                                        K k2, V v2,
                                        K k3, V v3); @SafeVarargs static List<T> listOf(T... orig);  }### Answer:
@Test public void testUnmodifiableMap() { final Map<String,Integer> one = B2Collections.unmodifiableMap(B2Collections.mapOf("a", 1)); thrown.expect(UnsupportedOperationException.class); one.put("mutation", 666); }