Adding comma separated strings to an ArrayList and vice versa

Question

How to add a comma separated string to an ArrayList? My string "returnedItems" could hold 1 or 20 items which I'd like to add to my ArrayList "selItemArrayList".

After the ArrayList has been populated, I'd like to later iterate through it and format the items into a comma separated string with no spaces between the items.

Answer 1

String returnedItems = "a,b,c";
List<String> sellItems = Arrays.asList(returnedItems.split(","));

Now iterate over the list and append each item to a StringBuilder:

StringBuilder sb = new StringBuilder();
for(String item: sellItems){
    if(sb.length() > 0){
        sb.append(',');
    }
    sb.append(item);
}
String result = sb.toString();

Answer 2

One-liners are always popular:

Collections.addAll(arrayList, input.split(","));