What type of collection copying do you prefer to use in your projects?

In Java, when copying collections, I prefer to use collection constructors or the addAll() method, as they provide shallow copying and are easy to use. For example:

List<String> original = new ArrayList<>();
original.add("one");
original.add("two");

// Creating a copy via constructor
List<String> copy = new ArrayList<>(original);

// Or via addAll
List<String> copy2 = new ArrayList<>();
copy2.addAll(original);

If a deep copy is needed (for example, a collection of objects that need to be copied themselves), then manual copying or third-party libraries are required. I prefer to avoid cloning via clone(), as it often leads to errors and is not always correctly implemented.

It is also worth noting that for immutable collections, methods from Collections.unmodifiableList() or new methods from Java 9+ can be used to create immutable copies.