How can I use Collectors instead of manually putting into ConcurrentHashMap in java 8

Question

How can I Use Collectors to collect in a ConcurrentHashMap instread of putting manually into ConcurrentHashMap

ConcurrentHashMap config         


        

Answer 1

You can use Collectors.toConcurrentMap

results.stream()
           .flatMap(res -> res.getSeries().stream())
           .flatMap(series -> series.getValues().stream())
           .collect(Collectors.toConcurrentMap(
                                  vals -> vals.get(1).toString(),
                                  vals -> vals.get(2).toString()));

Answer 2

We can do this as follows also:

results.stream()
       .flatMap(res -> res.getSeries().stream())
       .flatMap(series -> series.getValues().stream())
       .collect(Collectors.toMap(
                              vals -> vals.get(1).toString(),
                              vals -> vals.get(2).toString(),
                              (vals1,vals2) -> vals2,
                              ConcurrentHashMap::new);