CODEWITHSUNDEEP
javalistarraylist
freebil
freebil

Reputation: 21

When do I need to create new instance of the List?

When do I need to choose one or the other method for lists? What about the resources we use?

List<String> names = new ArrayList<>(something.getList);

List<String> names = something.getList;

Upvotes: 0

Views: 58

Answers (2)

alistaircol
alistaircol

Reputation: 1453

This is the preferred way to do things, it means later on you can change the List of names to be of a different implementation of List because List is the interface and ArrayList is the comcrete implementation. Later in life you may want to change this to be a LinkedList or other implementation that uses the List interface.

I would do like this:

List<String> names = new ArrayList<String>(something.getList());

Upvotes: 0

Antho Christen
Antho Christen

Reputation: 1329

Doing this List<String> names = something.getList; assigns another reference to the something.getList object namely names. With the other syntax you get a brand new names object. As for which to use, is it actually a question of what you need, if you need to pass around a list i'd suggest you to use an Immutable List.

Upvotes: 1

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