In Java:

    public static String twoArrays(int k, List<Integer> A, List<Integer> B) {

    // Ordering A in ascending order
   A.sort((a, b) -> Integer.compare(a, b));
   // Ordering B in descending order
   B.sort((a, b) -> Integer.compare(b, a));

   for(int i=0;i<A.size();i++){
    if(A.get(i) + B.get(i) < k){
    return "NO";
    }

   }

return "YES";

}