### Question:
StringUtils { public static byte[] getBytesFromArraysToString(final String bytesString) { ParametersChecker .checkParameter("Should not be null or empty", bytesString); final String[] strings = bytesString.replace("[", "").replace("]", "").split(", "); final byte[] result = new byte[strings.length]; try { for (int i = 0; i < result.length; i++) { result[i] = (byte) (Integer.parseInt(strings[i]) & 0xFF); } } catch (final NumberFormatException e) { throw new IllegalArgumentException(e); } return result; } private  StringUtils(); static byte[] getRandom(final int length); static byte[] getBytesFromArraysToString(final String bytesString); static String getClassName(final Object object); static final ThreadLocalRandom RANDOM; static final String LINE_SEP; }### Answer:
@Test public void testException() { try { StringUtils.getBytesFromArraysToString(null); fail("EXPECTING_EXCEPTION_ILLEGAL_ARGUMENT_EXCEPTION"); } catch (final IllegalArgumentException e) { } try { StringUtils.getBytesFromArraysToString(""); fail("EXPECTING_EXCEPTION_ILLEGAL_ARGUMENT_EXCEPTION"); } catch (final IllegalArgumentException e) { } try { StringUtils.getBytesFromArraysToString("[ 7, a6 ]"); fail("EXPECTING_EXCEPTION_ILLEGAL_ARGUMENT_EXCEPTION"); } catch (final IllegalArgumentException e) { } }