How to convert hash map keys into list?

Question

I have a hash map and I'm trying to convert the keys to a list. Here's the code:

List<ARecord> recs = new ArrayList<ARecord>();  HashMap<String, ARecord> uniqueRecs = new HashMap<String, ARecord>(); for(ARecord records:recs){     if(!uniqueRecs.containsKey(records.getId())){         uniqueRecs.put(records.getId(), records);     } } 

When I try to do

List<ARecord> finalRecs = new ArrayList<ARecord>(uniqueRecs.keySet()); 

The error:

The constructor ArrayList(Set) is undefined".

How can I convert Hashmap keys to List<ARecord> finalRecs?

Answer 1

Your uniqueRecs has String type of the key. You have to do:

List<String> keys = new ArrayList<>(uniqueRecs.keySet()); 

or

List<ARecord> values = new ArrayList<>(uniqueRecs.values());