Exercise 13.1 in the book. The topic is the Thread class
and the run() method.
Exercise 13.2 in the book. The topic is the synchronized keyword.
Exercise 13.3 in the book. The topic is threads and in particular the run and wait methods.
Exercise 13.7 in the book. The topic is synchronized methods.
Exercise 13.14 in the book. The topic is Piped I/O.
Exercise 13.9 in the book. The topic "busy waiting".