FND_MESSAGE Displaying only message code and not message text

--Application: The short name of the application this message is associated with. This short name references the application
--you associate with your message when
--you define it using the Messages form.
--
--Name: The message name that identifies your message. This name is identical to the name you use when you define your message

--using the Messages form. Message Dictionary names are not case sensitive (for example, MESSAGE_NAME is the same name as message_name).

--

--Procedure FND_MESSAGE.SET_NAME(application IN varchar2,
--                               name IN varchar2);
DECLARE
   l_message VARCHAR2 (4000);

BEGIN
   FND_MESSAGE.SET_NAME ('XXTST', 'XX_TEST_MSG_NAME');
   l_message := FND_MESSAGE.GET;   DBMS_OUTPUT.put_line(l_message);

END;

--Note:-IF FND_MESSAGE.GET displays only the message code whatever
--is passed in the 2nd parameter and not message text, then, it
--means either the "Application Short Name" or the "Message Name" is
--incorrect 
--Also, make sure the "Generate Messages" Concurrent Program is run
--from "Application Developer" responsibility