Date: 2016jul7 Language: Java Q. Java: Easy way to avoid duplicates in an ArrayList<> A. If the ArrayList is fairly short:

void addUnique(ArrayList<String> list, String item) { if (!list.contains(item)) { list.add(item); } }

If you always do this when appending you won't get any duplicates. If you are given an ArrayList which might have unwanted duplicates I would convert it into a HashSet then back into an ArrayList.

list = new ArrayList<String>(new HashSet<String>(list));