Helper to remove null references in a Java List?

Question

Given the following List:

List<String> list = new ArrayList<String>();  list.add("s1"); list.add("s2"); list.add(null); list.add("s3"); list.add(null); list.add("s4"); 

I need a helper class that removes null references. Something like:

SomeHelper.removeNullReference(list);

such that the list only contains "s1", "s2", "s4", "s4" (non-null references).

What should I use to fulfill this requirement?

Answer 1

list.removeAll(Collections.singleton(null)); 

Answer 2

Java 8 added Collection.removeIf(Predicate) that removes all elements matching the predicate, so you can remove all occurrences of null from a list (or any collection) with

list.removeIf(Objects::isNull); 

using java.util.Objects.isNull as a Predicate.

You can also use .removeIf(x -> x == null) if you prefer; the difference is very minor.