I said in the Zork II description that the exception classes would be one-liners. To be fair, if you have the ability to add a String to an IllegalDungeon/SaveFormatException object, then you need a constructor in there too.
Just to eliminate confusion, here is, verbatim, the complete code for the four Exception classes:
public class NoRoomException extends Exception {}
public class NoExitException extends Exception {}
public class IllegalDungeonFormatException extends Exception {
public IllegalDungeonFormatException(String e) {
super(e);
}
}
public class IllegalSaveFormatException extends Exception {
public IllegalSaveFormatException(String e) {
super(e);
}
}
The first of these four snippets should be in NoRoomException.java. The second should be in NoExitException.java. The third should be in IllegalDungeonFormatException.java. The fourth should be in IllegalSaveFormatException.java.
Now move on to step b.