code: public static String getMapParam(Map<String,String[]> queryMap,
  			String field) {
  		String arr[] = queryMap.get(field);
  		if (arr == null || arr.length == 0) {
  			return null;
  		}
  		return arr[0];
  	}
docs: Extract the first value in the array mapped to by field in queryMap
  @param queryMap the Map in which to search
  @param field the field value desired
  @return the first value in the array mapped to field in queryMap, if
  present, null otherwise