Things that I've changed...

1. Renamed the LinkedList variable that +Vivian  used in the mouseListener method to "teachers" instead of "n" (and made it global...because all of the methods in that class need it)
2. Changed all the method headings to private in the main class (except the mouseListener ones because they're abstract and must be declared public in the class for some reason? *shrug*). 
3. Adding the line: numberOfEntries = teacher.size(); every single time we add something. 
4. Changed the windowClosing listener on the menuFrame class, so when someone tries to close to program (pressing the 'x' button), you can ask whether they want to save it. 
1. Vivi - once you find out how to write to the file, maybe you can just copy and paste the code there.. :) 
5.