public static void main(String[] args) {
int[] x = {1, 2, 3};
int[] y = {4, 5, 6};
int[] merge = new int[x.length + y.length];
for (int i = 0; i < x.length; i++) {
merge[i] += x[i];
}
for (int i = 0; i < y.length; i++) {
merge[x.length + i] += y[i];
}
System.out.println(Arrays.toString(merge));
}