How to best create a Java 8 stream from a nullable object?

Question

What is the best/idiomatic way of doing a null check before getting a stream?

I have method that is receiving a List that might be null. So I can\'t jus

Answer 1

Java 8:

Optional.ofNullable(collection)
    .stream()
    .flatMap(Collection::stream)

Java 9:

Stream.ofNullable(collection)
    .flatMap(Collection::stream)

Apache Commons Collections 4:

import org.apache.commons.collections4.CollectionUtils;
CollectionUtils.emptyIfNull(collection)
    .stream()