What should be specified in the get() method when retrieving a single item from a List of type List, when the list length is 1?

If you have a list of type List with a length of 1 and need to get the single element, you should pass the index 0 to the get() method, as indexing in Java lists starts from zero.

Example:

List<String> list = new ArrayList<>();
list.add("element");
String singleElement = list.get(0); // Gets the first and only element

If you call get(1) or any other index different from 0, with a list length of 1, an IndexOutOfBoundsException will be thrown.