Java By Comparison

Avoid Switch Fallthrough

class BoardComputer {

    CruiseControl cruiseControl;

    void authorize(User user) {
        Objects.requireNonNull(user);
        switch (user.getRank()) {
            case UNKNOWN:
                cruiseControl.logUnauthorizedAccessAttempt();
            case ASTRONAUT:
                cruiseControl.grantAccess(user);
                break;
            case COMMANDER:
                cruiseControl.grantAccess(user);
                cruiseControl.grantAdminAccess(user);
                break;
        }
    }
}

Some programming language constructs are infamous because of all the bugs they’ve caused over the years. One of them is the switch, and you should be careful when you use it.

The method authorizeUser() you see here validates its parameters and checks for a null reference. It uses Objects.requireNonNull(), a handy parameter ...