Convert a Set<Integer> to a primitive array [duplicate]

Question

I am using the following code to convert a Set to int[]

Set<Integer> common = new HashSet<Integer>();
int[] myArray = (int[]) common.toArray();

the I got the following error:

 error: incompatible types: Object[] cannot be converted to int[]

What would be the most clean way to do the conversion without adding element one by one using a for loop? Thanks!

Answer 1

You usually do this:

Set<Integer> common = new HashSet<Integer>();
int[] myArray = common.stream().mapToInt(Integer::intValue).toArray();

Answer 2

Set<Integer> common = new HashSet<>();
int[] values = Ints.toArray(common);