The default locale of your application is determined in three ways.
First, unless you have explicitly changed the default, the getDefault() method returns the locale that was initially determined by the Java Virtual Machine (JVM) when it first loaded. That is,
the JVM determines the default locale from the host environment. The host environment’s locale is determined by the host operating system and the user preferences established on that system.
on some Java runtime implementations, the application user can override the host’s default locale by providing this information on the command line by setting the
user.variant system properties.