code: public static <T> void join(Collection<T> collection, String delimiter, StringBuilder sb) {
  		join(collection, delimiter, sb, new JoinCallback<T>() {
  			public void handle(StringBuilder sb, T value) {
  				sb.append(value);
  			}
  		});
  	}
docs: Joins a collection of values into a delimited list.
  @param collection the collection of values
  @param delimiter the delimiter (e.g. ",")
  @param sb the string builder to append onto
  @param <T> the value class