CODEWITHSUNDEEP
javanullsethashset
Mouna Cheikhna
Mouna Cheikhna

Reputation: 39658

Removing null references from a HashSet

Is there a simple way of removing null references from a HashSet like the way we can delete them from a List using list.removeAll(Collections.singletonList(null)) ?

Upvotes: 22

Views: 30400

Answers (2)

Tikhon Jelvis
Tikhon Jelvis

Reputation: 68152

A HashSet, being a set, only contains one "copy" of any object, which also means that it can only contain one instance of null. Thus, you can just use HashSet.remove(null).

Upvotes: 4

Joachim Sauer
Joachim Sauer

Reputation: 308149

Since a Set can not contain the same value twice (including null, if it is supported by the specific Set implementation), simply doing set.remove(null) would be sufficient.

Note that you don't even need to check for the existence of null before, because remove(null) will simply do nothing if the Set doesn't contain null.

Upvotes: 61

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