This may well be the first book to cover the Java Communications API. Sun includes a limited amount of documentation with the Java Communications API itself, mostly javadoc class library documentation. The latter is also available from Sun’s web site at http://java.sun.com/products/javacomm/javadocs/Package-javax.comm.html.
The RS-232 serial port and IEEE 1284 parallel port standards predate the Web and widespread use of the Internet. Thus, these standards are still available only on dead trees for the moment. A number of books do cover them in reasonable detail, including Scott Mueller’s Upgrading and Repairing PCs, 10th edition (Que, 1998, ISBN 0-7897-1636-4).
Several books discuss writing port-aware programs in a variety of languages. Although none yet use Java, it’s generally not hard to translate from the low-level C or Basic code to the equivalent code that uses the Java Communications API. The best book I’ve found for parallel ports is Jan Axelson’s Parallel Port Complete (Lakeview Research, 1996, ISBN 096508191-5).
There are more choices for serial port books, but the most comprehensive one is certainly Joe Campbell’s C Programmer’s Guide to Serial Communications (Sams, 1993, ISBN 0-672-30286-1). Despite the title, the first half of this 900-page tome is an exhaustive treatment of more or less language-independent serial communication hardware and protocols from 19th-century telegraphy to the present day.