Junior — Middle

How can a duplicate of a collection be made in memory?

sobes.tech AI

Answer from AI

To create a duplicate of a collection in memory in Java, you can use several approaches:

Copy constructor — many collections have a constructor that accepts another collection, creating a shallow copy:

List<String> original = new ArrayList<>();
original.add("A");
original.add("B");

List<String> copy = new ArrayList<>(original);

clone() method — some collections implement the Cloneable interface and have a clone() method that creates a shallow copy:

ArrayList<String> copy = (ArrayList<String>) original.clone();

Using streams — you can create a new collection by copying the elements:

List<String> copy = original.stream().collect(Collectors.toList());

Important: all these methods create a shallow copy — objects inside the collection are not cloned but their references are copied. For a deep copy, each element must be cloned individually.

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