<dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>30.1-jre</version> </dependency> ImmutableList<String> list = ImmutableList.of("apple", "banana", "orange"); Collection<String> filteredList = Collections2.filter(list, s -> s.length() > 3); Collection<String> transformedList = Collections2.transform(list, String::toUpperCase); ImmutableListMultimap<Integer, String> groupedMap = Multimaps.index(list, String::length); List<String> processedData = FluentIterable.from(list) .filter(s -> s.length() > 3) .transform(String::toUpperCase) .toList();