weblogic jsessionid

Question

I run Weblogic 10.3 locally and have a question about the sessionId that it generates. When i print session.getId() i see something that resembles this:

Answer 1

WebLogic Server use those IDs to maintain HTTP Session Affinity in the WebLogic Cluster In-Memory Replication model.

For those Web applications with the HTTP session replication enabled (at weblogic.xml deployment descriptor and disabled by default) WebLogic will keep a primary and a backup copy of your HTTP Session with the cluster.

To avoid cluster overhead, the WebLogic Proxy Plug-In (deployed in your Web Tier Layer) parse the session cookie and redirects every request to the WLS hosting your primary copy. In case of failure or overhead of the managed server hosting the primary session, the Proxy Plug-In redirects the request to the instance where your HTTP Session resides.

The Proxy Plugin will track a dynamic list of all the WebLogic Cluster Members as pairs (JVM IDs / IP:ports) to redirect every request appropriately.

If your app don't enable the in-memory replication feature your cookie will only include the JVM ID where your HTTP Sesion lives (the primary and unique copy).