Exception in thread “main” java.lang.Error: Unresolved compilation problems

Your problem is in this line: Message messageObject = new Message ();
This error says that the Message class is not known at compile time.

So you need to import the Message class.

Something like this:

import package1.package2.Message;

Check this out.

http://docs.oracle.com/javase/tutorial/java/package/usepkgs.html