The Java 2 Standard Edition discussion of security can be viewed from http://java.sun.com/j2se/1.5.0/docs/guide/security/index.html.
The J2EE 1.4 Tutorial chapter titled Security can be viewed from http://java.sun.com/j2ee/1.4/docs/tutorial/doc/index.html.
The Administration Guide chapter titled Chapter 10, Configuring Message Security.
The Developer's Guide chapter titled Securing Applications.