Free public beta until December 4, 2026:
every course is open, no card needed.
After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept.
How the beta works
List
An ordered sequence of elements that, unlike an array, can have any length.
java.util.List is an ordered collection indexed from 0; ArrayList is the usual modifiable one, LinkedList another, and List.of / List.copyOf create unmodifiable lists.