My code is god but results aren't ok
public class Solution {
    public static void main(String[] args) throws Exception
    {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        ArrayList<String> lista = new ArrayList<String>();

        for (int i = 0; i < 10; i++)
        {   String s = reader.readLine();
            lista.add(s);                    }

        ArrayList<String> wynik = doubleValues(lista);

        // Wyświetla wynik
    }

    public static ArrayList<String> doubleValues(ArrayList<String> lista)
    {
        for (int i = 0; i < 10; i++)
        {
            System.out.println(lista.get(i));
            System.out.println(lista.get(i));
        }

        return null;
    }
}