removeIf() of List is not working as intended

Question

Whenever I try to remove an element from a List using list.removeIf(condition) it throws UnsupportedOperationException:

public class Test 
{
    public static void main(final String[] args) 
    {
        String[] stringArray = new String[]{"A","B","C","D"}; 
        List<String> stringList = Arrays.asList(stringArray); 
        stringList.forEach(System.out::println); 
        stringList.removeIf((String string) -> string.equals("B")); 
        stringList.forEach(System.out::println); 
    }
}

Why is it not working?

It is throwing as I mentioned above – T-Bag Jun 20 '18 at 06:43 — T-Bag, Jun 20 '18 at 06:43

score 9 · Answer 1 · edited Jun 20 '18 at 06:45

9

Arrays.asList returns a fixed sized List - backed by the array you pass in - so, just as you can't remove (or add) elements from an array, you can't remove (or add) elements from the List.

Use a java.util.ArrayList in order to be able to remove elements:

List<String> stringList = new ArrayList<>(Arrays.asList(stringArray));

edited Jun 20 '18 at 06:45

Andy Turner

137,514
11
162
243

answered Jun 20 '18 at 06:38

Eran

387,369
54
702
768

score 0 · Answer 2 · answered Jun 20 '18 at 06:49

0

Array.asList method returns an ArrayList of type java.util.Arrays.ArrayList (which is read only and fixed size) and not the classic java.util.ArrayList (resizable and item-removable)

answered Jun 20 '18 at 06:49

sreeroop

64
1
9

removeIf() of List is not working as intended

2 Answers2