Java RMI by William Grosso (O'Reilly & Associates, 2002).
Effective Java by Joshua Bloch (Addison-Wesley Professional, 2001).
AspectJ web site at http://www.aspectj.org.
Command object articles. These are a series of articles I wrote for onjava.com. The first of the articles is at http://www.onjava.com/pub/a/onjava/2002/10/17/rmi.html.
Data expiration articles. These are a series of articles I wrote for onjava.com. The first of the articles is at http://www.onjava.com/pub/a/onjava/2002/01/09/dataexp1.html.