Lista Java Flatten
List<List<Object>> list = ...
List<Object> flat =
list.stream()
.flatMap(List::stream)
.collect(Collectors.toList());
Thoughtful Toad
List<List<Object>> list = ...
List<Object> flat =
list.stream()
.flatMap(List::stream)
.collect(Collectors.toList());
someMap.values().forEach(someList::addAll);