this is my answer:

   Integer[] number = {1,2,3};
    String[] s = {"Hello", "World"};
    List<String> list = new ArrayList<>();
    for(int i: number){
        list.add(Integer.toString(i));
    }
    for(String p: s){
        list.add(p);
    }
    for(String i: list){
        System.out.println(i);
    }