### Question:
JsonUtil { public static JsonNode readTree(String jsonString) throws JsonProcessingException { return mapper.readTree(jsonString); }  static String stringify(T value); static T fromJsonObject(String jsonString, Class<T> clazz); static List<T> fromJsonArray(String jsonString, 
			Class<T> elementClass); static JsonNode readTree(String jsonString); static T treeToValue(JsonNode node, Class<T> clazz); static Set<ValidationMessage> validate(JsonNode node, String schema);  }### Answer:
@Test public void readTree() throws JsonProcessingException { String jsonString = "{\"text\":\"a\",\"intNumber\":1,\"doubleNumber\":2.1,\"date\":\"2020-05-14T20:55:00\"}"; JsonNode rootNode = JsonUtil.readTree(jsonString); assertThat(rootNode.get("text").asText()).isEqualTo("a"); }