Many differences exist between J2EE agents and web agents in the way they perform tasks. However, the basic tasks they perform are similar. While the primary purpose of both types of agents is to enforce authentication and authorization before a user can access a protected resource, the two agent types differ in the kind of resources that they can protect and in the way they enforce such policy decisions.
When installed, a web agent automatically protects the entire set of resources available on the web server. On the other hand, J2EE agents only protect resources within a web application hosted on an application server after the web application has been configured to use the J2EE agent. Thus, if multiple web applications are hosted on an application server on which a J2EE agent has been installed, only the web applications that have been specifically configured to use the J2EE agent will be protected by the agent. Other applications will remain unprotected and can potentially malfunction if they depend upon any J2EE security mechanism.
Further, the J2EE agent can only protect resources that are packaged within a web or enterprise application. Certain application servers provide an embedded web server that can be used to host non-packaged web content such as HTML files and images. Such content cannot be protected by a J2EE agent unless it is redeployed as a part of a web application.
J2EE agents provide more modes of operation than do web agents. These modes are basically methods for evaluating and enforcing access to resources. You can set the mode according to your site's security requirements. For example, the SSO_ONLY mode is a less restrictive mode. This mode uses only OpenSSO Enterprise Authentication Service to authenticate users who attempt to access a protected resource.
Some of the modes such as SSO_ONLY and URL_POLICY are also achievable with web agents, whereas other modes of operation such as J2EE_POLICY and ALL modes do not apply to web agents. For web agents, by default, SSO_ONLY and URL_POLICY modes are both on. If you want only SSO set, enable the property labeled SSO Only Mode (Tab: Global, Name: com.sun.identity.agents.config.sso.only).
For both J2EE agents and web agents, the modes can be set in OpenSSO Enterprise Console.
In the J2EE_POLICY and ALL modes of operation, J2EE agents enforce J2EE declarative policies as applicable for the protected application.