Quote:

"If we compile this and run one thread under Sun's Java 1.1.7 on
a 4-CPU Sun machine the execution time is 13 seconds:"

Note that this does not include startup costs (the time required to
set up the Java Virtual Machine, load the class file, instantiate
any objects, and create the main thread). These can be estimated as
shown below (obviously the absolute time value is not comparable, as
both the hardware and the Java Virtual Machine differ). To estimate
the Java Virtual Machine setup time:

martin@living:~/WebPerf/ch16> time java -version
java version "1.4.0"
Java(TM) 2 Runtime Environment, Standard Edition(build 1.4.0-b92)
Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)

real 0m1.677s
user 0m1.620s
sys 0m0.040s

And because the bulk of the processing is performed by the threads
(the main method merely launches the threads - at 50 milliseconds or
so, this can be ignored), a better measure of the overall startup
costs (the Virtual Machine, plus class loading, object creation and
the main thread) can be derived as follows:

martin@living:~/WebPerf/ch16> time java Loop 0

real 0m2.265s
user 0m2.140s
sys 0m0.110s

These costs will be relatively constant for any number of threads,
and can be safely ignored for performance purposes when amortized
over many threads.

This is not really a technical mistake (possibly it's an omission),
but I thought it was interesting enough to include here for others
to read.

Compile with 'java jdbcCxnTest'.

Should be:

Compile with 'javac jdbcCxnTest.java'. Obtain a usage message with
'java jdbcCxnTest'.