"en" is the language code specified by ISO 639. while US is country code specified by 3166.
In Java, the Locale object recognizes the language as languageCode_countryCode (e.g. en_US) and not as languageCode-countryCode.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…