Is there a way to get the value of a HashMap randomly in Java?

Question

Is there a way to get the value of a HashMap randomly in Java?

Answer 1

Since the requirements only asks for a random value from the HashMap, here's the approach:

1. The HashMap has a values method which returns a Collection of the values in the map.
2. The Collection is used to create a List.
3. The size method is used to find the size of the List, which is used by the Random.nextInt method to get a random index of the List.
4. Finally, the value is retrieved from the List get method with the random index.

Implementation:

HashMap map = new HashMap();
map.put("Hello", 10);
map.put("Answer", 42);

List valuesList = new ArrayList(map.values());
int randomIndex = new Random().nextInt(valuesList.size());
Integer randomValue = valuesList.get(randomIndex);

The nice part about this approach is that all the methods are generic -- there is no need for typecasting.