code: public static <T> String join(Collection<T> collection, String delimiter) {
  		StringBuilder sb = new StringBuilder();
  		join(collection, delimiter, sb);
  		return sb.toString();
  	}
docs: Joins a collection of values into a delimited list.
  @param collection the collection of values
  @param delimiter the delimiter (e.g. ",")
  @param <T> the value class
  @return the final string