code: public String getCharacterEncoding() {
  
  		if (this.message.getContentEncoding() != null) {
  			return this.message.getContentEncoding().getEncoding();
  		} else {
  			ContentTypeHeader cth = (ContentTypeHeader)
  				this.message.getHeader(ContentTypeHeader.NAME);
  			if(cth == null) return null;
  			return cth.getParameter("charset");
  		}
  	}
docs: /*
  (non-Javadoc)
  @see javax.servlet.sip.SipServletMessage#getCharacterEncoding()