LeetCode: Java anagram function not working for the last test case

Question

I was solving this LeetCode problem and can't figure out why one of my solutions doesn't work for the last test case.

public boolean isAnagram(String s, String t) {
    if (s.length() != t.length()) {
        return false;
    }

    HashMap<Character, Integer> sHashMap = new HashMap<>();
    HashMap<Character, Integer> tHashMap = new HashMap<>();

    for (char c : s.toCharArray()) {
        sHashMap.put(c, sHashMap.getOrDefault(c, 0) + 1);
    }

    for (char c : t.toCharArray()) {
        tHashMap.put(c, tHashMap.getOrDefault(c, 0) + 1);
    }

    if (!sHashMap.keySet().equals(tHashMap.keySet())) {
        return false;
    }

    for (char c : sHashMap.keySet()) {
        if (sHashMap.get(c) != tHashMap.get(c)) {
            return false;
        }
    }

    return true;
}

The last test case has two very long strings and my function returns false instead of true.

EDIT: It was because I was comparing Integer objects using !=.