How can I collect a Java 8 stream into a Guava ImmutableCollection?

The toImmutableList() method in the accepted answer of Alexis is now included in Guava 21 and can be used as:

ImmutableList<Integer> list = IntStream.range(0, 7)
    .boxed()
    .collect(ImmutableList.toImmutableList());

Edit: Removed @Beta from ImmutableList.toImmutableList along with other frequently used APIs in Release 27.1 (6242bdd).