FULL PRODUCT VERSION :
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b18)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b18, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Windows 10 x64

A DESCRIPTION OF THE PROBLEM :
java.time.format.TextStyle.FULL_STANDALONE does not work well while formatting months.

For example:
System.out.println(Month.of(3).getDisplayName(TextStyle.FULL_STANDALONE, Locale.ENGLISH));

Output is "3", but it should be "March".

It works well, when java.time.format.TextStyle.FULL is used:
System.out.println(Month.of(3).getDisplayName(TextStyle.FULL, Locale.ENGLISH));

Output is "March".

I think that java.time.format.TextStyle.FULL_STANDALONE works well for languages, where the output should be different, for example Czech:

System.out.println(Month.of(3).getDisplayName(TextStyle.FULL_STANDALONE, new Locale("cs")));

Output is "březen", that is OK.

System.out.println(Month.of(3).getDisplayName(TextStyle.FULL, new Locale("cs")));

Output is "března", that is OK too.


REPRODUCIBILITY :
This bug can be reproduced always.