code: static public String format(Collection<?> collection, String property){
  		return format(collection, property, ",", true);
  	}
docs: Format a collection's elements' properties to ',' separated string, with trimming on the elements' properties<br>
  @param collection	The collection that will be formatted
  @param property		The property of the collection's element that will be put into the result string.
  Please see PropertyUtils.getProperty() of commons-beanutils for detail.
  @return	A string containing separated properties of the collection's elements