This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
MTA stands for Mail Transfer Agent, I think, so apparently the app runs, but cannot use its email services.
I recommend that when running Java via cron that you place the actual Java command in a script file and let cron run the script instead. It makes things a little simpler. You can run the script directly for debugging purposes (which is something I spent too much time doing just the other day!).
An IDE is no substitute for an Intelligent Developer.