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The Collectors.toList Method
The Collectors.toList Method
//The following example retrieves the names of each member in the
//collection roster and groups them by gender:
Map<Person.Sex, List<String>> namesByGender =
roster
.stream()
.collect(
Collectors.groupingBy(
Person::getGender,
Collectors.mapping(
Person::getName,
Collectors.toList())));Accumulates the stream elements into a new instance of List.
As with most operations in the Collectors class, the toList operator returns an instance of Collector, not a collection.