### Question:
SuccinctTrie extends Dictionary { public void compress() { checkUncompressed("compress is only allowed once"); List<HelpNode> nodesInOrder = createNodesInOrder(); selectZeroCache = new int[nodeCount + 1]; int position = 2; int zeroesWritten = 1; selectZeroCache[1] = 1; for (HelpNode node : nodesInOrder) { position+=node.children.size(); zeroesWritten++; selectZeroCache[zeroesWritten] = position; position++; } root = null; compressed = true; } SuccinctTrie(); @JsonCreator static SuccinctTrie fromSerialized(SerializedSuccinctTrie serialized); @Override int add(byte[] bytes); @Override int put(byte[] key); void checkCompressed(String errorMessage); void checkUncompressed(String errorMessage); void tryCompress(); void compress(); @Override @JsonIgnore int getId(byte[] value); boolean containsReverse(int intValue); void getReverse(int intValue, IoBuffer buffer); @Override int size(); boolean isEmpty(); List<byte[]> getValuesBytes(); @Override Iterator<DictionaryEntry> iterator(); @JsonValue SerializedSuccinctTrie toSerialized(); SuccinctTrie uncompress(); @Override byte[] getElement(int id); @Override long estimateMemoryConsumption();  }### Answer:
@Test public void serializationTest() throws JsonParseException, JsonMappingException, JsonProcessingException, IOException, JSONException { SuccinctTrie dict = new SuccinctTrie(); DirectDictionary direct = new DirectDictionary(dict); dict.setDataset(new DatasetId("test")); dict.setName("testDict"); data().forEach(direct::put); dict.compress(); SerializationTestUtil .forType(Dictionary.class) .test(dict); }