As far as I know, you can't convert a String into a Collection but you can definately convert an array of strings into Collection using Arrays.asList() method which returns a fixed size List...and List IS A Collection !!!
"History would be kind to me, for I intend to write it."
Strings and collections are two entirely different things. What do you expect the collection you want to contain? Do you want a collection with one element (the string itself)? Or do you want a collection that contains the characters in the string as separate elements?