Is it possible to dump an image of a running JVM and later restore the previous state by loading the image into the JVM? I'm fairly certain the answer is negative, but would love to be wrong.
With all the dynamic languages available for the JVM comes an increase in interactivity, being able to save a coding session would help save time manually restoring the VM to a previous session.
This is currently not possible in any of the JVMs I know. It would not be very difficult to implement something like this in the JVM if programs run disconnected from their environments. However, many programs have hooks into their environment (think file handles, database connections) which would make implementing something like this very hairy.
There was a JSR 323 proposed for this a while back but it was rejected. You can find some links in those articles about the research behind this and what it would take. It was mostly rejected as an idea that was too immature.
I have heard of at least one startup (unfortunately don't recall the name) that was working on a virtualization technology over a hypervisor (probably Xen) that was getting pretty close to being able to move JVMs, including even things like file system refs and socket endpoints. Because they were at the hypervisor level, they had access to all of that stuff. By hooking that and the JVM, they had most of the pieces. I think they might have gone under though.
The closest thing you can get today is Terracotta, which allows you to cluster a portion of your JVM heap, storing it in a server array, which can be made persistent. On JVM startup, you connect to the cluster and can continue using whatever portions of your heap are specified as clustered. The actual objects are faulted in on an as-needed basis.