Maven: <dependency> <groupId>com.github.javadev</groupId> <artifactId>underscore-java</artifactId> <version>1.36</version> </dependency> Gradle: groovy implementation 'com.github.javadev:underscore-java:1.36' List<Person> filteredList = _.filter(personList, p -> p.getAge() < 18); List<Integer> doubledList = _.map(intList, i -> i * 2); Optional<Person> firstAdult = _.find(personList, p -> p.getAge() >= 18); _.each(personList, p -> System.out.println(p.getName())); List<Person> resultList = _.chain(personList) .filter(p -> p.getAge() < 18) .sortBy(Person::getName) .value();