public void testEnumMap() throws Exception { ObjectMapper mapper = new ObjectMapper(); String JSON = "{ \"KEY1\" : \"\", \"WHATEVER\" : null }"; // to get typing, must use type reference EnumMap<Key, String> result = mapper.readValue(JSON, new TypeReference<EnumMap<Key, String>>() {}); assertNotNull(result); assertEquals(EnumMap.class, result.getClass()); assertEquals(2, result.size()); assertEquals("", result.get(Key.KEY1)); // null should be ok too... assertTrue(result.containsKey(Key.WHATEVER)); assertNull(result.get(Key.WHATEVER)); // plus we have nothing for this key assertFalse(result.containsKey(Key.KEY2)); assertNull(result.get(Key.KEY2)); }