code: public String getParameter(String name) {
  		if(name == null) {
  			throw new NullPointerException("the parameter given in parameter is null !");
  		}
  		String value = this.parameters.get(name);
  		if(value != null) {
  			return RFC2396UrlDecoder.decode(value);
  		} else {
  			if("lr".equals(name)) return "";// special case to pass Addressing spec test from 289 TCK
  		}
  		return null;
  	}
docs: /*
  (non-Javadoc)
  @see javax.servlet.sip.Parameterable#getParameter(java.lang.String)