Java

A slightly annoying discussion was going on tonight on a Java IRC channel. It was all about how to remove null elements from an ArrayList.

There have been a lot of questions by various people. Besided suggestions, technical questions, there have also been the
usual suspects like "Why on earth are you adding null elements anyway?".

But let's have a look at the result, which seems to be the easiest way:

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

If you don't know the Collections class, you might have been come up with something like this:

list.removeAll(Arrays.asList(new Object[]{null}));

Is there any other way to remove null references from collections? For example by using HashSets and only use remove(null). Or is it better to implement your own implementation of a Collection which does it itself?
What are the performance benefits of each variation? Could we use the Java High Performance Collections implementation Trove?

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