ConfigResolutionStrategy { void activate() { nodes().flatMap(e -> e.allKeysRecursively()) .distinct() .forEach(key -> { activate(key); }); } ConfigResolutionStrategy();   ConfigResolutionStrategy(Properties properties); private  ConfigResolutionStrategy(PropertiesManipulator properties); void withFilter(ConfigurationFilter filter); Object valueOf(ConfigKey key);  }
@Test public void testCompletelyEmpty() { Properties props = new Properties(); ConfigResolutionStrategy strategy = new ConfigResolutionStrategy(props); strategy.activate(); }