You can pass a java array to Arrays.asList(Object).
List<String> fixedSizeList = Arrays.asList(new String);
You cannot insert new Strings to the fixedSizeList (it already has 100 elements). You can only set its values like this:
fixedSizeList.set(7, "new value");
That way you have a fixed size list. The thing functions like an array and I can't think of a good reason to use it. I'd love to hear why you want your fixed size collection to be a list instead of just using an array.