Given the following: <fmt:message key="mkey" bundle="${application.tBundle}"/> According to section 8.2, page 8-69 a <fmt:message> action with a 'bundle' attribute will establish a localization context using the specified ResourceBundle. This is verified by the fact that ServletResponse.setLocale() is not called in this case per section 8.4, page 8-75: "More specifically, the response's setLocale() method is alwasy called by the <fmt:locale> action (see Section 8.5). In addition, it is called by the following actions: - Any <fmt:bundle> action (see Section 8.6) - Any <fmt:message> action that establishes a localization context"