[FEATURE] Why annotation `@Cleanup` use a singletonList to judge null

[samho2008]

Java Code:

    public static void main(String[] args) throws IOException {
        @Cleanup Reader fileReader = new FileReader("hello.txt");
    }

Decompiled Class Code:

    public static void main(String[] args) throws IOException {
        Reader fileReader = new FileReader("hello.txt");
        if (Collections.singletonList(fileReader).get(0) != null) {
            fileReader.close();
        }

    }

The question is why use a singletonList to judge null, instead of fileReader != null?

[Rawi01]

Historical reasons I guess, the message of the commit that added theses lines:

Rewritten @Cleanup's new null analysis prevention to not use
Lombok.preventNullAnalysis but go with Collections.singletonList(expr).get(0)
instead; while this does create a pointless object, it doesn't cause a clash
when eclipse has lombok 0.10 installed but the project uses 0.9, which doesn't
have preventNullAnalysis. Eventually, once 0.9 is long forgotten, this can be reverted.

[magicprinc]

I think @Cleanup is a great feature and must not be abandoned, but improved!

The bad thing is: if a "close" method throws an exception, it completely replaces the original exception from the body. Better: Swallow the exception from close Event better Java 7 Suppressed exceptions