<dependency> <groupId>com.github.javafunk</groupId> <artifactId>jacksandra</artifactId> <version>2.4.0</version> </dependency> import com.github.underscore.__; import com.github.underscore.Optional; List<Student> students = getStudents(); __.each(students, student -> System.out.println(student.getName() + " " + student.getAge())); Optional<Student> student = __.find(students, student -> student.getAge() > 18); List<String> studentNames = __.map(students, Student::getName); int totalAge = __.reduce(students, 0, (sum, student) -> sum + student.getAge());