How to preserve insertion order in HashMap? [duplicate]
LinkedHashMap
is precisely what you're looking for.
It is exactly like HashMap
, except that when you iterate over it, it presents the items in the insertion order.
HashMap
is unordered per the second line of the documentation:
This class makes no guarantees as to the order of the map; in particular, it does not guarantee that the order will remain constant over time.
Perhaps you can do as aix suggests and use a LinkedHashMap
, or another ordered collection. This link can help you find the most appropriate collection to use.