Java 16: Stream.toList()

Fahd ShariffApril 15th, 2021Last Updated: April 13th, 2021

1 247 1 minute read

Java 16 introduces a handy new Stream.toList() method which makes it easier to convert a stream into a list. The returned list is unmodifiable and calls to any mutator method will throw an UnsupportedOperationException.

Here is some sample code:

import java.util.stream.Stream;
import static java.util.stream.Collectors.*;
 
// Java 16
stream.toList(); // returns an unmodifiable list
 
// Other ways to create Lists from Streams:
 
stream.collect(toList());
 
stream.collect(toCollection(LinkedList::new)); // if you need a specific type of list
 
stream.collect(toUnmodifiableList());  // introduced in Java 10
 
stream.collect(
    collectingAndThen(toList(), Collections::unmodifiableList)); // pre-Java 10