Java HashMap: How to get a key and value by index?

Question

I am trying to use a HashMap to map a unique string to a string ArrayList like this:

HashMap>

Basical

Answer 1

You can do:

for(String key: hashMap.keySet()){
    for(String value: hashMap.get(key)) {
        // use the value here
    }
}

This will iterate over every key, and then every value of the list associated with each key.