How to see HTTP session content using PSI Probe?

You could use PSI Probe.

Drop probe.war into the webapps folder of your Tomcat, open the probe context in the browser (f.e. localhost:8080/probe) and at “Applications|/MYCONTEXT|Sessions|/SESSIONIDXYZ” you can see the session content of session SESSIONIDXYZ of the context MYCONTEXT.

psiprobe

[Update] Monitoring tomcat instances

Here are some OSS projects to monitor your tomcat instances (f.e. memory-/cpu-usage, sessions, mbeans)

Off course you can also monitor your tomcat via VisualVM (http://visualvm.java.net/ or included in JDK6)

Update: Or use JRDS http://jrds.fr/