CODEWITHSUNDEEP
javamemory-managementarraylistinteger
user1539090
user1539090

Reputation: 75

memory usage of ArrayList<Integer>

I’m using ArrayList<Integer> in my research project. I need to keep unknown number of integers in this list. Sometimes I need to update the list: remove existing records or add new records. As Integer is an object, it’s taking much more memory than only int. Is there any alternate way to maintain the list that will consume less memory than Integer?

Upvotes: 5

Views: 2400

Answers (4)

Simulant
Simulant

Reputation: 20102

You should also think about an alternativ storage system to you ArrayList. As for the linking mechanisim every Element has a overhead consuming (sometimes) more memory as the value itself. Maybe you don't need them ordered. Have you thought about a Map oder a simple Set if this is applicable or implement your own data structure?

Upvotes: 0

Johanna Larsson
Johanna Larsson

Reputation: 10761

That depends on the language you use, but I assume it's Java. In Java, as you probably know, you can't use ints in ArrayList, because they are a primitive datatype. To use ints, you'd have to use regular arrays, which are fixed size. That means you need to create a new array of a larger size each time you add something, assuming that makes the number of elements larger than the array. You trade memory for complexity, as you have to write a lot more code and mess around with moving ints back and forth.

The reduced memory use is unlikely to be worth the work and the extra risk of bugs in implementing such a solution.

Upvotes: 0

jspcal
jspcal

Reputation: 51894

Try an integer list implementation that is optimized for memory usage, such as the one from the Colt library:

http://acs.lbl.gov/software/colt/api/cern/colt/list/IntArrayList.html

Java Integer objects usually require more overhead than an int primitive, so you need an implementation that is space-optimized.

From Colt:

Scientific and technical computing, as, for example, carried out at CERN, is characterized by demanding problem sizes and a need for high performance at reasonably small memory footprint. [...]

Upvotes: 5

user
user

Reputation: 3088

You could use an array with int-s and write your own methods with the same logic, that ArrayList does. But IMO that is a bad idea - modern machines have enough memory to use Integer objects, trust me... :)

Upvotes: 0

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