Sanalista

import java.util.ArrayList;
import java.util.Scanner;
import java.util.HashMap;

public class Sanalista {
    public static void main(String[] args) {
        Scanner lukija = new Scanner(System.in);
        ArrayList<String> sanat = new ArrayList<>();

        int n = Integer.valueOf(lukija.nextLine());

        for (int i = 0; i < n; i++) {
            String syote = lukija.nextLine();

            if (syote.length() % 2 == 0) {
                sanat.add(syote);
            }
        }

        for (int i = 0; i < sanat.size(); i++) {
            HashMap<Character, Integer> kirjaimet = new HashMap<>();
            String sana = sanat.get(i);

            for (int k = 0; k < sana.length(); k++) {
                char kirjain = sana.charAt(k);
                kirjaimet.put(kirjain, kirjaimet.get(kirjain) + 1);
            }

            for (Integer lkm : kirjaimet.values()) {
                if (lkm % 2 != 0) {
                    sanat.remove(i);
                }
            }
        }

        System.out.println(sanat.size());
    }
}

Test 1

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.NullPointerException
	at Sanalista.main(Sanalista.jav...

Test 2

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.NullPointerException
	at Sanalista.main(Sanalista.jav...

Test 3

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.NullPointerException
	at Sanalista.main(Sanalista.jav...