Most of the time, however, you'll want to pass the information to other parts of the program. You can store the result of the calculation in a field and provide a getter method to return the value of that field.
p. 133: In the first paragraph,
change "Notice the addition of a start() method"
to "Notice the addition of the calculateDigest() method to start the thread."
join() method including the noargs variant can throw
an InterruptedException. Thus the first method signature on the page should be:
public final void join() throws InterruptedException