### Question:
JsonUtils { public static boolean isJsonArray(String value) { if (Strings.isEmptyOrBlank(value)) { return false; } final String trimmed = value.trim(); return trimmed.charAt(0) == '[' && trimmed.charAt(trimmed.length() - 1) == ']'; } private  JsonUtils(); static ObjectReader reader(); static T readFromStream(final InputStream stream, final Class<T> type); static ObjectWriter writer(); static ObjectMapper copyObjectMapperConfiguration(); static Map<String, Object> map(Object... values); static T convertValue(final Object fromValue, final Class<T> toValueType); static boolean isJson(String value); static boolean isJsonObject(String value); static boolean isJsonArray(String value); static List<String> arrayToJsonBeans(JsonNode json); static String jsonBeansToArray(List<?> jsonBeans); static String toPrettyString(Object value); static String toString(Object value);  }### Answer:
@Test public void isJsonArray() { assertThat(JsonUtils.isJsonArray(null)).isFalse(); assertThat(JsonUtils.isJsonArray("")).isFalse(); assertThat(JsonUtils.isJsonArray("{}")).isFalse(); assertThat(JsonUtils.isJsonArray("[]")).isTrue(); assertThat(JsonUtils.isJsonArray("[{\"foo\": \"bar\"}]")).isTrue(); assertThat(JsonUtils.isJsonArray(" [{\"foo\": \"bar\"}] ")).isTrue(); assertThat(JsonUtils.isJsonArray("\n[{\"foo\": \"bar\"}]\n")).isTrue(); }