Exception messages (for both server and client) should be translated. Exceptions thrown from the server should not have a message, but rather an identifier that maps it to a i18n item and the values of variables. Additionally:

• The exception message should be a sentence, so it should end with punctuation (normally a ".", avoid the use of "!").
• Mention as many variable as possible+relevant and mention them with this pattern: "variableName (" + variable + ")".