Java:

public static int makingAnagrams(String s1, String s2) {
    Map<Character, Integer> s1Map = new HashMap<>();
    Map<Character, Integer> s2Map = new HashMap<>();
    int delCount = 0;
    for (char c : s1.toCharArray()) {
        s1Map.merge(c, 1, (a,b) -> a + b);
    }
    for (char c : s2.toCharArray()) {
        s2Map.merge(c, 1, (a,b) -> a + b);
    }
    for (Map.Entry<Character, Integer> e : s1Map.entrySet()) {
        if (e.getValue() > s2Map.getOrDefault(e.getKey(),0)) {
            delCount += e.getValue() - s2Map.getOrDefault(e.getKey(),0);
        }
    }
    for (Map.Entry<Character, Integer> e : s2Map.entrySet()) {
        if (e.getValue() > s1Map.getOrDefault(e.getKey(),0)) {
            delCount += e.getValue() - s1Map.getOrDefault(e.getKey(),0);
        }
    }
    return delCount;
}