Is the value returned by the Collections.empty() methods always constant?

Asked Jul 31 '19 at 00:57

Active Jul 31 '19 at 02:02

Viewed 32 times

This returns true in my trite little example:

List<Object> a = Collections.emptyList();

System.out.println(a == Collections.emptyList());

Is there an instance where a previous call to Collections.emptyList() might not equal Collections.emptyList() on a subsequent call? Is the result constant?

The implementation suggests so:

public static final List EMPTY_LIST = new EmptyList<>();

public static final <T> List<T> emptyList() {
    return (List<T>) EMPTY_LIST;
}

But how safe is it to rely on it outside of this particular implementation? The documentation doesn't explicitly state that it is constant.

edited Jul 31 '19 at 02:02

asked Jul 31 '19 at 00:57

Zhro

2,546
2
29
39

Do you mean to ask "is the value returned a constant"? – Hovercraft Full Of Eels Jul 31 '19 at 00:59
1

What is the meaning of `final`? Also see javadocs *Implementations of this method need not create a separate List object for each call.* – Scary Wombat Jul 31 '19 at 01:03
@flakes The note in the documentation is included in the accepted answer for duplicate question. Even if I reopen this question, there is not really anything more to answer is there? – Scary Wombat Jul 31 '19 at 01:51

Is the value returned by the Collections.empty() methods always constant?

0 Answers0