public class Test {
    public static void main(String[] args) {
        Pair<Integer,String> pair=new Pair<>(1,"a");
        System.out.println(pair.getKey());
        System.out.println(pair.getValue());
        Pair<String,Integer> swappedPair=Pair.swap(pair);
        System.out.println(swappedPair.getKey());
        System.out.println(swappedPair.getValue());
    }
}