Lowercase all HashMap keys

Question

I \'ve run into a scenario where I want to lowercase all the keys of a HashMap (don\'t ask why, I just have to do this). The HashMap has some millions of entries.

At fir

Answer 1

the concerns in the above answers are correct and you might need to reconsider changing the data structure you are using.

for me, I had a simple map I needed to change its keys to lower case

take a look at my snippet, its a trivial solution and bad at performance

private void convertAllFilterKeysToLowerCase() {
    HashSet keysToRemove = new HashSet();
    getFilters().keySet().forEach(o -> {
        if(!o.equals(((String) o).toLowerCase()))
            keysToRemove.add(o);
    });
    keysToRemove.forEach(o -> getFilters().put(((String) o).toLowerCase(), getFilters().remove(o)));
}