How to Add Multiple Elements to List At Once in Java

I needed a way to add multiple elements to my ArrayList simultaneously.

How can we do that without a loop?

Using ArrayList.addAll()

We can add all items from another collection to an ArrayList using addAll().

List<String> lst = new ArrayList<>();
lst.addAll(Arrays.asList("corgi", "shih tzu", "pug"));

First, we would have to define a new list using Arrays.asList().

Then, we can call addAll() on the original list.

Using Collections.addAll()

We can use the Collections class, which contains many static methods to operate on collections.

Using addAll(), we can add any number of elements into our collection.

List<String> lst = new ArrayList<>();
Collections.addAll(lst, "corgi", "shih tzu", "pug");

Using List.of()

As of Java 9, we can use List.of() to instantiate an immutable list.

So, if this fits your use case, feel free to use this.

List<String> lst = List.of("corgi", "shih tzu", "pug");