public static JsonNode get(String property, JsonNode node) {
    Preconditions.checkArgument(
        node.hasNonNull(property), "Cannot parse missing field: %s", property);
    return node.get(property);
  }
@Test
  public void get() throws JsonProcessingException {
    assertThatThrownBy(() -> JsonUtil.get("x", JsonUtil.mapper().readTree("{}")))
        .isInstanceOf(IllegalArgumentException.class)
        .hasMessage("Cannot parse missing field: x");

    assertThatThrownBy(() -> JsonUtil.get("x", JsonUtil.mapper().readTree("{\"x\": null}")))
        .isInstanceOf(IllegalArgumentException.class)
        .hasMessage("Cannot parse missing field: x");

    assertThat(JsonUtil.get("x", JsonUtil.mapper().readTree("{\"x\": \"23\"}")).asText())
        .isEqualTo("23");
  }