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Best way to convert a collection into an array in java

Anonymous User 1803 08-Oct-2015
I am trying to convert ArrayList into integer array, but its throwing CTE, Is it possible to convert directly a collection into an array i.e. is there any  build-in utility class or method for doing this thing only?
java java  collection  array 
Updated on 08-Oct-2015
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Anonymous User

Anonymous User

08-Oct-2015
Hi Elizabeth, 
There is nothing build-in to convert a collection to an array as far as i know.
You may need to create a method which use Iterator or listIterator(in case of list) and iterate on all the elements of the collection through it and convert it by type casting into prmitive type and assign the value in the array. Pass your collection inside this method. folloe below code :
public static int[] convertIntegers(List<Integer> integers)
{
    int[] ret = new int[integers.size()];
    Iterator<Integer> iterator = integers.iterator();
    for (int i = 0; i < ret.length; i++)
    {
        ret[i] = iterator.next().intValue();
    }
    return ret;
}


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