@HiveDecimalVersionV1
  @Override
  public boolean equals(Object obj) {
    if (obj == null || obj.getClass() != getClass()) {
      return false;
    }
    return fastEquals((HiveDecimal) obj);
  }
Are two decimal content (values) equal?
<p>
@param obj   The 2nd decimal.
@return  When obj is null or not class HiveDecimal, the return is false.
         Otherwise, returns true when the decimal values are exactly equal.
storage-api/src/java/org/apache/hadoop/hive/common/type/HiveDecimal.java