Diagram showing positioning of Java ES system service components against the various levels in the distributed infrastructure services, previously described. Higher-level components generally depend on lower-level components.
The infrastructure services, in levels from top to bottom are: integration, user collaboration, security and policy, runtime, messaging, persistence, network transport, and operating system platform.
The positioning of Java Enterprise System components is the following:
Portal Server is at the integration level.
Messaging Server, Instant Messaging, and Calendar Server are at the user collaboration level.
Access Manager is at the security and policy level.
Web Server spans the runtime and messaging levels.
Application Server spans the runtime, messaging, and persistence levels.
Message Queue is at the messaging level.
Directory Server is at the persistence level.
The Solaris, Linux, Windows, and HP-UX operating systems span the network transport and operating system platform levels.