In java, there is introduced support for BCP-47 language tags. But the Unicode extensions are restricted to calendars and numbers. With Java 10, java.util.Locale and connected classes are modernized to apparatus additional Unicode extensions are defined in LDML defining. Some new extensions are added and given below.
java.text.DateFormat::get*Instance java.text.DateFormatSymbols::getInstance java.text.DecimalFormatSymbols::getInstance java.text.NumberFormat::get*Instance java.time.format.DateTimeFormatter::localizedBy java.time.format.DateTimeFormatterBuilder::getLocalizedDateTimePattern java.time.format.DecimalStyle::of java.time.temporal.WeekFields::of java.util.Calendar::{getFirstDayOfWeek,getMinimalDaysInWeek} java.util.Currency::getInstance java.util.Locale::getDisplayName java.util.spi.LocaleNameProvider