### Question:
RLP { public static byte[] encodeByte(byte singleByte) { if ((singleByte & 0xFF) == 0) { return new byte[]{(byte) OFFSET_SHORT_ITEM}; } else if ((singleByte & 0xFF) <= 0x7F) { return new byte[]{singleByte}; } else { return new byte[]{(byte) (OFFSET_SHORT_ITEM + 1), singleByte}; } }  static int decodeInt(byte[] data, int index); static BigInteger decodeBigInteger(byte[] data, int index); static byte[] decodeIP4Bytes(byte[] data, int index); static int getFirstListElement(byte[] payload, int pos); static int getNextElementIndex(byte[] payload, int pos); static void fullTraverse(byte[] msgData, int level, int startPos,
                                    int endPos, int levelToIndex, Queue<Integer> index); static byte getCommandCode(byte[] data); @Nonnull static ArrayList<RLPElement> decode2(@CheckForNull byte[] msgData); static RLPList decodeList(byte[] msgData); @Nullable static RLPElement decode2OneItem(@CheckForNull byte[] msgData, int startPos); @Nonnull static UscAddress parseUscAddress(@Nullable byte[] bytes); @Nonnull static Coin parseCoin(@Nullable byte[] bytes); @Nullable static Coin parseCoinNonNullZero(byte[] bytes); @Nullable static Coin parseSignedCoinNonNullZero(byte[] bytes); static Coin parseCoinNullZero(@Nullable byte[] bytes); @Nullable static BlockDifficulty parseBlockDifficulty(@Nullable byte[] bytes); static byte[] encode(Object input); static byte[] encodeLength(int length, int offset); static byte[] encodeByte(byte singleByte); static byte[] encodeShort(short singleShort); static byte[] encodeInt(int singleInt); static byte[] encodeString(String srcString); static byte[] encodeBigInteger(BigInteger srcBigInteger); static byte[] encodeUscAddress(UscAddress addr); static byte[] encodeCoin(@Nullable Coin coin); static byte[] encodeCoinNonNullZero(@CheckForNull Coin coin); static byte[] encodeSignedCoinNonNullZero(@CheckForNull Coin coin); static byte[] encodeCoinNullZero(Coin coin); static byte[] encodeBlockDifficulty(BlockDifficulty difficulty); static byte[] encodeElement(@Nullable byte[] srcData); static byte[] encodeListHeader(int size); static byte[] encodeLongElementHeader(int length); static byte[] encodeSet(Set<ByteArrayWrapper> data); static byte[] encodeList(byte[]... elements);  }### Answer:
@Test public void test4() { byte[] expected = {(byte) 0x80}; byte[] data = encodeByte((byte) 0); assertArrayEquals(expected, data); byte[] expected2 = {(byte) 0x78}; data = encodeByte((byte) 120); assertArrayEquals(expected2, data); byte[] expected3 = {(byte) 0x7F}; data = encodeByte((byte) 127); assertArrayEquals(expected3, data); }