code: public void writeComment(String data) throws XMLStreamException {
  		if (preserveComment) {
  			try {
  				this.checkPendingATEvents();
  				// TODO improve EXI API
  				char[] chars = data.toCharArray();
  				encoder.encodeComment(chars, 0, chars.length);
  			} catch (Exception e) {
  				throw new XMLStreamException(e.getLocalizedMessage(), e);
  			}
  		}
  	}
docs: /*
  Writes an xml comment with the data enclosed
  
  (non-Javadoc)
  
  @see javax.xml.stream.XMLStreamWriter#writeComment(java.lang.String)