Recently received the following error when attempting to deploy a new war file on my Glassfish server:
Cannot create JDBC driver of class 'com.mysql.jdbc.Driver' for connect URL 'jdbc:hsqldb:mem:grailsDB'
The solution to the issue however, has nothing to do with MySQL and drivers whatsoever. The problem was that I mistyped the environment name when creating the war file.
I typed grails rstaging war instead of grails staging war. This is just another example of extremely useful error messages that I've encountered while developing for Grails.