Want to warn callers that they should think twice before invoking a method?

public final class SeriouslyException extends Exception {
    private SeriouslyException() {}
}

Use it like this:

public void deployNukes() throws SeriouslyException {
    // ...
}

Then

try {
    deployNukes();
} catch (SeriouslyException e) {
    // Execution will never reach here.
}