UnsupportedOperationException - the removeAll method is not supported by this collection (Java Collections)

Question

Set<Badge> availableBadges = myService.getAvailableBadges();
List<Badge> allBadges = Arrays.asList(Badge.values());
allBadges.removeAll(availableBadges);
/* Badge is an enumn */

what collections do support remove all ?

Answer 1

Arrays.asList returns a partially unmodifiable implementation (in part of remove* methods - thanks to @LouisWasserman for the remark) of the List interface.

EDIT 1: Use an ArrayList wrapper on it: new ArrayList<Badge>(allBadges);

Answer 2

Your collection might be unmodifiable.

You need to create new List

List<T> list = new ArrayList<>(unmodifiableList);

Now your list is modifiable and you can perform remove and removeAll operations.