Question

Just curious, but when I try to use this to reverse an array it always spits out some incoherent gibberish instead of the array reversed, such as [I@43256ea2. Any ideas as to why it does this?

public class Fiddle {
    public static void main(String[] args) {
        int[] number = {1,2,3,4,5};
        System.out.println(reverse(number));
    }
    public static int[] reverse(int[] a) {
        int[] b = new int[a.length];
        for (int i = 0; i < a.length; i++) {
            b[a.length-1-i] = a[i];
        }
        return b;
    }
}

Thanks for any ideas as to why this is happening (it’s probably because I’m forgetting something though).

Answer 1

Use the utility method java.util.Arrays.toString(int[]):

System.out.println(Arrays.toString(reverse(number)));

Array classes do not override Object.toString(), meaning they use the default implementation provided by Object, which is “type@hashcode_in_hex“. The String representation of the type int[] is [I, which is why you are seeing this “incoherent gibberish.”