Increment all values in a Map by 1

What's the neatest way to increment all values in a HashMap by 1? The map is `, but the key doesn't matter as every value will be incremented.

Is it "cleaner" to use lambdas with forEach/compute`/etc. or just loop through the entries?

HashMap map = mobCounter.get(mob);
for (Entry e : map.entrySet()) {
    map.put(e.getKey(), e.getValue() + 1);
}

This doesn't look too messy to me but I'm wondering if people like seeing lambdas more.

You must not modify the keys of a HashMap while iterating over it. You are just lucky it worked.

Instead of the put(...), write e.setValue(e.getValue() + 1).

If you have some kind of Multiset available (e.g. when you are using Guava), you could replace your HashMap with a Multiset, which will make your intention clearer.

Using lambdas, your code would look like:

map.replaceAll((k, v) -> v + 1);

This looks very nice to me. It cannot get any shorter.

StackExchange Code Review Q#148218, answer score: 8