Detect collections using double brace initialization

[gaul]

Some call sites construct collections via double brace initialization:

new HashSet<String>() {{ add("NU"); add("TK"); add("NC"); add("AC"); }};

error-prone should recommend the more succinct and efficient:

new HashSet<String>(Arrays.asList("NU", "TK", "NC", "AC"));

The former creates an anonymous inner class and an implicit this reference which can prolong the outer class lifetime:

https://blog.nishtahir.com/2015/09/27/why-you-shouldnt-use-the-double-brace-initializer/

[JakeWharton]

Or suggest Set.of, List.of, or Map.of in about 45 days when Java 10 is out.

…

On Sat, Jan 27, 2018, 9:46 PM Andrew Gaul ***@***.***> wrote: Some call sites construct collections via double brace initialization: new HashSet<String>() {{ add("NU"); add("TK"); add("NC"); add("AC"); }}; error-prone should recommend the more succinct and efficient: new HashSet<String>(Arrays.asList("NU", "TK", "NC", "AC")); The former creates an anonymous inner class and an implicit this reference which can prolong the outer class lifetime: https://blog.nishtahir.com/2015/09/27/why-you-shouldnt-use-the-double-brace-initializer/ — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#914>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAEEEYTmsaMpKsq7VLoxgksGUgWLSNQHks5tO9-WgaJpZM4RvinU> .

[JakeWharton]

Oops that's in Java 9!

…

On Sat, Jan 27, 2018, 9:50 PM Jake Wharton ***@***.***> wrote: Or suggest Set.of, List.of, or Map.of in about 45 days when Java 10 is out. On Sat, Jan 27, 2018, 9:46 PM Andrew Gaul ***@***.***> wrote: > Some call sites construct collections via double brace initialization: > > new HashSet<String>() {{ add("NU"); add("TK"); add("NC"); add("AC"); }}; > > error-prone should recommend the more succinct and efficient: > > new HashSet<String>(Arrays.asList("NU", "TK", "NC", "AC")); > > The former creates an anonymous inner class and an implicit this > reference which can prolong the outer class lifetime: > > > https://blog.nishtahir.com/2015/09/27/why-you-shouldnt-use-the-double-brace-initializer/ > > — > You are receiving this because you are subscribed to this thread. > Reply to this email directly, view it on GitHub > <#914>, or mute the thread > <https://github.com/notifications/unsubscribe-auth/AAEEEYTmsaMpKsq7VLoxgksGUgWLSNQHks5tO9-WgaJpZM4RvinU> > . >

[jbduncan]

Or even Guava's Immutable* collections?