Errata

The previously confirmed errata for the print version with the following description is also true of the current ebook version.

"
In text you explain that you don't have a readIn.close(); in the constructor but only in the finalize method. But in the example code you have a readIn.close(); right after the object has been read.

Note from the Author or Editor:
The line
readIn.close();
in the try block of the constructor should be removed.
"

The boolean variable "done" is not declared volatile nor accessed using any other synchronization action, so there is no guarantee that its updated value will be visible to the thread calling the isDone method.

Fix:

private volatile boolean done = false;

[After further inspection, please replace the previous report with the following -JAB]

The boolean variable "done" is not declared volatile nor is it accessed using any other synchronization action, so there is no guarantee that its updated value will be visible to the thread calling the isDone method.

The simplest fix for this is to add "volatile" to the declaration:

private volatile boolean done = false;

The same criticism also applies to "roster" and this can also be addressed by adding "volatile".

In addition, as a matter of good concurrent style, the "fromHost" and "forTeam" instance variables assigned in the constructor should be declared final.

At this point I think some mention of FutureTask is required. Ideally, RosterRetriever would be a FutureTask -- a class that already provides thread-safe isDone and get() methods.

The "base3" and "base4" cases in the switch statement are missing their terminating "break" statements, resulting in invalid results in these cases.

The "base3" and "base4" cases in the switch statement are missing their terminating "break" statements, resulting in invalid results in these cases.