Create mutable List from array?

One simple way:

Foo[] array = ...;
List<Foo> list = new ArrayList<Foo>(Arrays.asList(array));

That will create a mutable list – but it will be a copy of the original array. Changing the list will not change the array. You can copy it back later, of course, using toArray.

If you want to create a mutable view onto an array, I believe you’ll have to implement that yourself.