A new powerful collection library saves us from source.stream().really("?").collect(sink()) pipelines.

List<String> names = persons
        .filter(p -> p.age > 12)
        .map(Person::getName);

The functional For is an expression that yields a value. The result is a lazy evaluated collection of elements.

Iterator<String> iterator =
    For(persons.filter(Person::hasAddress), p ->
        For(p.addresses).yield(a ->
             p.name   ","   a.street
        )
    );

Vavr and Java are fully interoperable.

java.util.List<Integer> result =
    iterator.map(String::length).asJava();

Structural pattern matching is an easy way to decompose values. The result is ... a value!

Number num = Match(personOption).of(
    Case($Some($Person($())), person -> 1.0d),
    Case($None(), 0)
);

The Try monad represents the result state of a computation which may be a Success or a Failure.

R result = Try(() -> mightFail())
   .recover(x -> ...)
   .getOrElse(defaultValue);

Java's Optional is not Serializable. We use Vavr's Option for remote operations. Check out our JSON module!

class Person implements Serializable {
    final Option<String> title;
    final String name;
    ...
}