private void validate() {
    if (tagType == -1) {
      throw new IllegalArgumentException(TAG_TYPE_NOT_SET_EXCEPTION);
    }
    if (tagBytes == null) {
      throw new IllegalArgumentException(TAG_VALUE_NULL_EXCEPTION);
    }
  }
Builder implementation to create {@link Tag}<br>
Call setTagValue(byte[]) method to create {@link ArrayBackedTag}
hbase-common/src/main/java/org/apache/hadoop/hbase/TagBuilderFactory.java