Examples of scanner errors in Java books?

I'm practicing HashSet from the Java books of cay S. Horstmann and Gary Cornell, and I think there's an error in the sample code on page 687 We have a word imported by scanner into HashSet, which looks like this (I deleted some unnecessary code to make a more obvious problem):

Set<String> words = new HashSet<String>();
Scanner in = new Scanner(system.in);
while (in.hasNext()) {
    String word = in.next();
    words.add(word);
}

The problem is that there is no way to stop the cycle Or maybe something I'm missing?

To stop the loop, I added another static helper:

public static boolean isStop(Scanner in) {
    if (in.next().equals("stop")) {
        return true;
    }
    return false;
}

Now the main code looks like this:

Set<String> words = new HashSet<String>();
Scanner in = new Scanner(system.in);
while (!isStop(in)) {
    String word = in.next();
    words.add(word);
}

Is there any other way to stop the scanner from cycling? I can't believe the author of this book made a mistake?

Solution

Once this condition is false, the cycle stops:

in.hasNext()

That is, no more words

Inside the loop is a command to read the next word:

in.next()

Therefore, words will continue to be read until the scanner cannot read more words The loop will terminate at the end of anything the scanner is reading