There are two ways to change the default locale. The first is to set it on the command line:
> java -Duser.language=2-char-language-code -Duser.region=2-char-country-code MyApp
// Set only language code
> java -Duser.language=en -Duser.region= MyApp
// Set language and country code
> java -Duser.language=en -Duser.region=US MyApp
The second way to change the default locale is to call Locale.setDefault():
// Get default locale
Locale locale = Locale.getDefault();
// Set the default locale to pre-defined locale
Locale.setDefault(Locale.US);
// Set the default locale to custom locale
locale = new Locale("en", "US");
Locale.setDefault(locale);
> java -Duser.language=2-char-language-code -Duser.region=2-char-country-code MyApp
// Set only language code
> java -Duser.language=en -Duser.region= MyApp
// Set language and country code
> java -Duser.language=en -Duser.region=US MyApp
The second way to change the default locale is to call Locale.setDefault():
// Get default locale
Locale locale = Locale.getDefault();
// Set the default locale to pre-defined locale
Locale.setDefault(Locale.US);
// Set the default locale to custom locale
locale = new Locale("en", "US");
Locale.setDefault(locale);