Locale (@NotNull final PropertiesFile propertiesFile) { String name = propertiesFile.getName(); if (!StringUtil.containsChar(name, '_')) return DEFAULT_LOCALE; final String containingResourceBundleBaseName = propertiesFile.getResourceBundle().getBaseName(); if (!name.startsWith(containingResourceBundleBaseName)) return DEFAULT_LOCALE; return getLocale(name.substring(containingResourceBundleBaseName.length())); }