See recommendation from Naoto in
<http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-September/020594.html>

<<
Just one comment. When you are retrieving the default locale, please use
Locale.getDefault(Locale.Category.DISPLAY) which returns the default
locale for displaying translatable names.

Locale.Category was introduced in JDK7 where the user can set the
default locales separately for UI display names and Formatting. In your
case, the resource bundle seems to contain user visible localizable
strings, so I suggested using getDefault() with Locale.Category.DISPLAY
specifically. That way the user would see the string in the correct
language even on any custom default locale environment.
>>

There are possibly several places in the corelibs where Locale.getDefault(Category.DISPLAY) should be preferred to Locale.getDefault().

e.g. Logging, ResourceBundle etc...