code: protected static String getParameter(HttpServletRequest request, String[] aliases) {
  		final String sourceMethod = "getParameter"; //$NON-NLS-1$
  		boolean isTraceLogging = log.isLoggable(Level.FINER);
  		if (isTraceLogging) {
  			log.entering(sourceClass, sourceMethod, new Object[]{request.getQueryString(), Arrays.asList(aliases)});
  		}
  		Map<String, String[]> params = request.getParameterMap();
  		String result = null;
  		for (Map.Entry<String, String[]> entry : params.entrySet()) {
  			String name = entry.getKey();
  			for (String alias : aliases) {
  				if (alias.equalsIgnoreCase(name)) {
  					String[] values = entry.getValue();
  					result = values[values.length-1];	// return last value in array
  				}
  			}
  		}
  		if (isTraceLogging) {
  			log.exiting(sourceClass, sourceMethod, result);
  		}
  		return result;
  	}
docs: Returns the value of the requested parameter from the request, or null
  
  @param request
  the request object
  @param aliases
  array of query arg names by which the request may be specified
  @return the value of the param, or null if it is not specified under the
  specified names