### Question:
Utils { public static String dateTimeFormat(Date dateTime) { DateFormat iso8601 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US); iso8601.setTimeZone(UTC); return iso8601.format(dateTime); }  static byte[] bigIntegerToBytes(BigInteger b, int numBytes); static void uint16ToByteArrayLE(int val, byte[] out, int offset); static void uint32ToByteArrayLE(long val, byte[] out, int offset); static void uint32ToByteArrayBE(long val, byte[] out, int offset); static void int64ToByteArrayLE(long val, byte[] out, int offset); static void uint16ToByteStreamLE(int val, OutputStream stream); static void uint16ToByteStreamBE(int val, OutputStream stream); static void uint32ToByteStreamLE(long val, OutputStream stream); static void uint32ToByteStreamBE(long val, OutputStream stream); static void int64ToByteStreamLE(long val, OutputStream stream); static void uint64ToByteStreamLE(BigInteger val, OutputStream stream); static int readUint16(byte[] bytes, int offset); static long readUint32(byte[] bytes, int offset); static long readInt64(byte[] bytes, int offset); static long readUint32BE(byte[] bytes, int offset); static int readUint16BE(byte[] bytes, int offset); static int readUint16FromStream(InputStream is); static long readUint32FromStream(InputStream is); static byte[] reverseBytes(byte[] bytes); static byte[] sha256hash160(byte[] input); static BigInteger decodeMPI(byte[] mpi, boolean hasLength); static byte[] encodeMPI(BigInteger value, boolean includeLength); static BigInteger decodeCompactBits(long compact); static long encodeCompactBits(BigInteger value); static Date rollMockClock(int seconds); static Date rollMockClockMillis(long millis); static void setMockClock(); static void setMockClock(long mockClockSeconds); static Date now(); static long currentTimeMillis(); static long currentTimeSeconds(); static String dateTimeFormat(Date dateTime); static String dateTimeFormat(long dateTime); static boolean checkBitLE(byte[] data, int index); static void setBitLE(byte[] data, int index); static void sleep(long millis); static void setMockSleep(boolean isEnable); static void passMockSleep(); static void finishMockSleep(); static int maxOfMostFreq(int... items); static int maxOfMostFreq(List<Integer> items); static boolean isAndroidRuntime(); static boolean isLinux(); static boolean isWindows(); static boolean isMac(); static final Joiner SPACE_JOINER; static final BaseEncoding HEX; static volatile Date mockTime; }### Answer:
@Test public void dateTimeFormat() { assertEquals("2014-11-16T10:54:33Z", Utils.dateTimeFormat(1416135273781L)); assertEquals("2014-11-16T10:54:33Z", Utils.dateTimeFormat(new Date(1416135273781L))); }