Summary

Specify that the set returned from Locale.getISOCountries(Locale.IsoCountryCode type) is unmodifiable.

Problem

Locale.getISOCountries(Locale.IsoCountryCode type) returns an unmodifiable Set. This behavior is not specified in the method, and users can encounter an unexpected java.lang.UnsupportedOperationException if they attempt to modify the returned Set.

Solution

Specify the returned set is unmodifiable. This behavior is consistent with the other Set returning methods of Locale.

Specification

In Locale.getISOCountries(Locale.IsoCountryCode type),

-     * {@return a {@code Set} of ISO3166 country codes for the specified type}
+     * {@return an unmodifiable {@code Set} of ISO3166 country codes for the specified type}