Question

Suppose that I have a HashMap() defined and allocated like this:

private HashMap<Integer, Integer> rankCombinator=new HashMap<>();

I am always “building” the HashMap with keys and values before accessing it, for example I am storing 15 Integers on it as keys with their corresponding values I want. I am trying to traverse this map using a for-each loop:

for(Map.Entry<Integer, Integer> entry : rankCombinator.entrySet())
{
   // More code here.
}

I suppose this loop won’t return the values sorted in the way they were inputted in the the first place. Am I right? If yes, is there any pattern in the values returned?
I have tried looking over the documentation but it doesn’t seem like it includes a pattern for this.

Answer 1

The HashMap implementation makes no guarantees about the order the items are returned, I would suggest using a LinkedHashMap which retains order.

private Map<Integer, Integer> rankCombinator=new LinkedHashMap<Integer, Integer>();

Api Documentation