For the method Arrays.copyOf:

static <T,U> T[] copyOf(U[] original, int newLength, Class<? extends T[]> newType)

The erased type is

static Object[] copyOf(Object[] original, int newLength, Class newType)

However, the following code returns a value array, which is not supposed to be castable to an Object[].

import java.util.Arrays;
public class Test {
    static final value class V {
        public final int v1;
        private V () {v1 = 0;}
    }

    public static void main(String args[]) {
        Object oa[] = new Object[1];
        oa[0] = V.default;

        System.out.println(Arrays.copyOf(oa, oa.length, V[].class).getClass());
    }
}

$ java -XX:+EnableValhalla -cp . Test
class [QTest$V;