Question

I’m using Netbeans.
When I run the program below, I get this as output [I@de6ced! How come?

import java.util.Arrays;
import java.util.Vector;

public class Test {

public static void main (String[] args) {
     int[] a = new int[1];
     a[0] = 5;
     Vector<Integer> a1 = new Vector(Arrays.asList(a));
     System.out.println(a1.elementAt(0));
 }
}

I also tried working around it but then I got a

Exception in thread “main” java.lang.ClassCastException: [I cannot be cast to java.lang.Integer
at TopCoder.Test.main(Test.java:13)
Java Result: 1

public static void main (String[] args) {
    int[] a = new int[1];
    a[0] = 5;
    Vector<Integer> a1 = new Vector(Arrays.asList(a));

    int b = a1.elementAt(0); /* EXCEPTION THROWN HERE */
    System.out.println(b);
}

Answer 1

Integer[] a = new Integer[1];
a[0] = new Integer(5);
List list = Arrays.asList(a);
System.out.println(list.get(0));

The above works as you would expect.

So it looks like the “int” array is treated like an Object and not an array of Integers. In other words auto boxing doesn’t seem to be applied to it?