package container; // Suggested in the textbook. /** Runtime exception thrown when someone tries to modify/remove an * entry in an adaptable data structure. If the entry isn't currently * in the data structure (e.g., it's already been removed), then we'd * better complain by throwing a different exception. */ public class InvalidEntryException extends RuntimeException { public InvalidEntryException() { } public InvalidEntryException(String err) { super(err); } }