Key Differences Between List.of and Arrays.asList in Java

General Discussions
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From my experience, one of the key distinctions lies in immutability. When you use java list.of, it creates an immutable list, which means that once it’s created, you can’t modify the contents—no adding, removing, or updating the elements. If you try to modify the list, you’ll get an UnsupportedOperationException. For example:

List<Integer> list1 = List.of(1, 2, 3); // Immutable  
list1.add(4); // Throws UnsupportedOperationException

In contrast, Arrays.asList returns a fixed-size list. You can modify the elements, but you can’t add or remove any items. For instance:

List<Integer> list2 = Arrays.asList(1, 2, 3); // Fixed size  
list2.set(0, 99); // Works fine  
list2.add(4); // Throws UnsupportedOperationException

So, if you need a list that should never be modified, java list.of is definitely the better choice.