@HiveDecimalWritableVersionV2
  public void setFromBytes(byte[] bytes, int offset, int length, boolean trimBlanks) {
    fastReset();
    isSet = fastSetFromBytes(bytes, offset, length, trimBlanks);
    if (!isSet) {
      fastReset();
    }
  }
Set the writable's current value to the decimal in a UTF-8 byte slice.
<p>
Afterwards, the isSet() method will return true, unless byte slice could not be converted.
storage-api/src/java/org/apache/hadoop/hive/serde2/io/HiveDecimalWritable.java