Dynamic Array List size

Question

How can I set size of a dynamic array with Java?

I tried setsize(...) with the array variable but not working. How can I do this?

Solution 1

array size needs to be fixed while initialization, use List instead and then have array from List using toArray()

For example:

List<Integer> listOfInt = new ArrayList<Integer>(); //no fixed size mentioned
listOfInt .add(1);
listOfInt .add(2);
listOfInt .add(3);
//now convert it to array 
Integer[] arrayOfInt = list.toArray(new Integer[listOfInt .size()]);

Solution 2

Your title is confusing. Are you using an ArrayList or an Array.
An ArrayList expands and shrinks as needed each time you call the add, remove method respectively (or any other add/remove variant). There is no need to manage its size yourself.

A list is initialized as follows:

List<Integer> lst = new ArrayList<Integer>();

Now you have a list where you can add a virtual infinite amount of elements.

An array needs its size on initialization which cannot be changed without reinitializing.

Comments

[Tudor]

Maybe suggest ArrayList in particular, since it actually uses an array under the hood?

[Andres F.]

+1 Almost surely the OP is trying to ask about ArrayList, but it's confusing.

[jmj]

Yes you could use ArrayList implementation as @Tudor mentioned in comment

[Admin]

List<Integer>[911] A = new ArrayList<Integer>(); but says it is not statement, im confused

[jmj]

Added example, it would help more