Null safe Collection as Stream in Java 8

You could use Optional :

Optional.ofNullable(collection).orElse(Collections.emptySet()).stream()...

I chose Collections.emptySet() arbitrarily as the default value in case collection is null. This will result in the stream() method call producing an empty Stream if collection is null.

Example :

Collection<Integer> collection = Arrays.asList (1,2,3);
System.out.println (Optional.ofNullable(collection).orElse(Collections.emptySet()).stream().count ());
collection = null;
System.out.println (Optional.ofNullable(collection).orElse(Collections.emptySet()).stream().count ());

Output:

3
0

Alternately, as marstran suggested, you can use:

Optional.ofNullable(collection).map(Collection::stream).orElse(Stream.empty ())...