Definition: Message classes are created within an ABAP project at the ABAP package level. They are used to group messages within a development object. So, you can combine related messages and reuse them in other programs. After creating a message class, you add the individual messages.
Message: Messages notify a user about unexpected behaviour, an error, a status, or a result of an action. An application will display the message at runtime. A message is specified by a unique 3-digit message number, a single-digit language key, text information, and a message class.
Message: Messages notify a user about unexpected behaviour, an error, a status, or a result of an action. An application will display the message at runtime. A message is specified by a unique 3-digit message number, a single-digit language key, text information, and a message class.