AliasMap { public Map<String, String> toMap() { Map<String, String> map = new HashMap<>(params); for (Map.Entry<String, String> entry : aliases.entrySet()) { String alias = entry.getKey(); String paramKey = entry.getValue(); map.put(alias, get(paramKey)); } return Collections.unmodifiableMap(map); }  String putAlias(String alias, String key); String get(String key); String put(String key, String value); Map<String, String> toMap(); boolean containsAllKeys(Collection<String> keys); boolean containsKey(String key);  }
@Test public void testComputedMapNotNull() throws Exception { Assertions.assertThat(new AliasMap().toMap()).isNotNull(); }