public static String join(List<?> list, String separator) {

		return join(list, separator, null);
	}
public static String join(List<?> list, String separator) {

		return join(list, separator, null);
	}
public static String join ( List < ? > list , String separator ) { return join ( list , separator , null ) ; }
Joins list of string items to a single string, where items are separated
with a defined separator.

@param list      to join into string
@param separator to be used between elements
@return items joined into a single string
Joins list of string items to a single string where items are separated with a defined separator .