Conversion Object[] to int[] error [duplicate]

Question

Possible Duplicate:
How to convert List<Integer> to int[] in Java?

I have an ArrayList and when I try to convert it into an Array of Integer because I need to do operations which concerns integer, I get this error :

incompatible types
required: int[]
found: java.lang.Object[]

Here's my code :

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

// I execute an SQL statement, then :
while (resultat.next()) {
    ids_rdv.add(resultat.getInt("id_rdv"));
}
int[] element_rdv_id = ids_rdv.toArray(); //Problem

Do you have any idea about that?

Naze

Answer 1

Assuming your original objects were instances of the Integer class:

Integer[] element_rdv_id = ids_rdv.toArray(new Integer[0]);

Wound

Thank you !! It works now !! but I still don't understand what did you do ? – Naze

Simply Integer isn't the same data type as int. Also if you later need any value from this Integer[] array you may need to use element_rdv_id[i].intValue() instead of element_rdv_id[i] as you would expect. – Primal

thank you @Primal :) what about new Integer[0] ? – Naze

Have a look here – Primal

Answer 2

incompatible types required: int[] found: java.lang.Object[]

when you do ids_rdv.toArray(), it returns an array of Objects, that can't be assigned to array of primitive integer types.

You need to get an array of Integer objects in hand, so write it this way

Integer[] element_rdv_id = ids_rdv.toArray(new Integer[]);

Maddiemadding

Thank you Ahmad, I understand now, answer upvoted ;) – Naze