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package Streams; import java.util.Arrays; import java.util.Collection; import java.util.List; import java.util.stream.Collectors; public class FlatMapExample { public static void main(String[] args) { List> listOfLists = Arrays.asList( Arrays.asList("a", "b"), Arrays.asList("c", "d"), Arrays.asList("e", "f") ); listOfLists.stream() .flatMap(Collection::stream) .map(String::toUpperCase) .forEach(System.out::println); } }