chapter 7 (on connection management and coupling) are especially poignant
examples. Organization is undeniably the other dominant theme. Chapters 3
and 4 deal with a model-view-controller organization that will improve main-
tenance and readability.
You should be aware of several assumptions I make as I build the examples
in the topic:
In many cases, examples are bitter by design . Our approach is to refac-
tor the same base program in order to resolve one problem at a time.
Many known problems are not solved until late in the text. Obviously,
code in this topic should not unthinkingly be pasted into production
Most of the programming examples are complete rather than discussed
through code fragments. Because they place at your fingertips all of the
details that you need to follow the conversation, I hope that under-
standing the argument in this part will be easier.
The exception management in the examples is intentionally sparse. This
keeps them brief and helps us maintain our focus on the bitter lessons
You can download the code from this part at your convenience from
Chapters 3 and 4 will discuss a modern version of the Model-View-Controller
design pattern; chapter 5 will improve the performance of that design through
caching; chapter 6 will address Java memory management; chapter 7 will deal
with connections and coupling; and chapter 8 will deal with EJB s. In truth, I
could have organized the topic differently. I settled on this structure because it
provided a logical refactoring of a single application through successive steps
that flowed freely and smoothly. The initial examples build a bulletin board
system. A cache improves the performance, and memory-management tech-
niques help manage the cache. Connection pooling provides a cache of sorts
for database connections. We finally look at how this project might be done
with a bitter EJB implementation. While this organization provides a free-
flowing book, it may be admittedly more awkward as a reference text. Such
are the day-to-day compromises of a starving author.
And now, let's roll up our sleeves and attack the bitter business at hand.