How do I remove repeated elements from ArrayList?
If you don't want duplicates in a Collection, you should consider why you're using a Collection that allows duplicates. The easiest way to remove repeated elements is to add the contents to a Set (which will not allow duplicates) and then add the Set back to the ArrayList:
Set<String> set = new HashSet<>(yourList);yourList.clear();yourList.addAll(set);Of course, this destroys the ordering of the elements in the ArrayList.
Although converting the ArrayList to a HashSet effectively removes duplicates, if you need to preserve insertion order, I'd rather suggest you to use this variant
// list is some List of StringsSet<String> s = new LinkedHashSet<>(list);Then, if you need to get back a List reference, you can use again the conversion constructor.
In Java 8:
List<String> deduped = list.stream().distinct().collect(Collectors.toList());Please note that the hashCode-equals contract for list members should be respected for the filtering to work properly.