CODEWITHSUNDEEP
javaarraylistcollectionsreference
Vishnupriya
Vishnupriya

Reputation: 19

Adding object to ArrayList without reference

Can I add an object to an ArrayList without a reference?

For example, can I add object as below:

ArrayList<Dog> list=new ArrayList<Dog>();      
list.add(new Dog);

Upvotes: 0

Views: 2964

Answers (3)

Kariem
Kariem

Reputation: 4873

Yes you can.

If you don't reference the new dog anywhere else, it will be up for garbage collection as soon as the list is eligible for garbage collection. See also this answer.

In addition to the other suggested improvements to your example code, you should

Your code would then look like this:

List<Dog> list = new ArrayList<>();   
list.add(new Dog());

Upvotes: 0

Jordi Castilla
Jordi Castilla

Reputation: 26961

You cannot do this:

list.add(new Dog);

but this:

list.add(new Dog());

Why can this be done?
 Actually is quite simple, JVM will automatically keep a reference of the created object inside the List to keep it alive, so you don't have to care about. As usual, if this object is removed from the list and not referenced anywhere else, will be elegible for Garbage Collector.

Upvotes: 3

shruti1810
shruti1810

Reputation: 4037

Yes, you can. Once you add the object to arrayList, what matters in only where the object is in the heap. It does not matter, you add it with reference or without.

But yes, it should be list.add(new Dog()).

You are missing the paranthesis after Dog.

Upvotes: 1

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