Add multiple items to already initialized arraylist in java

Question

I\'m googling it and can\'t seem to find the syntax. My arraylist might be populated differently based on a user setting, so I\'ve initialized it

Answer 1

Collections.addAll is a varargs method which allows us to add any number of items to a collection in a single statement:

List list = new ArrayList<>();
Collections.addAll(list, 1, 2, 3, 4, 5);

It can also be used to add array elements to a collection:

Integer[] arr = ...;
Collections.addAll(list, arr);