I think Patracia means a hot upgrade. Eg install new jvm, migrate without shutdown, state could be transferred using serialization.
----- Original message ----- > Sorry, I don't think that makes sense. It's rarely a problem to run 1.5 > code in a 1.6 JVM. Instead the problem is usually that there is no 1.6 > JVM available on the system. I've had two real-world cases: older OS > (Fedora Core 3 and Mac OS 10.4) and licensing (an redistribution > agreement with Sun that covered only 1.4 and 1.5). > > Chris > > -----Original Message----- > From: Patricia Shanahan [mailto:p...@acm.org] > Sent: Friday, July 01, 2011 12:57 PM > To: dev@river.apache.org > Subject: A thought on JVM migration > > I've seen some discussion of using a separate JVM for security. Does it > also provide a solution to the problem of JVM migration in a > continuously operating River-based system? > > Suppose the objective is to migrate from 1.5 to 1.6. > > The first step would be to get each client and server into a state in > which it can recognize that a proxy needs 1.6, and spawn a 1.6 JVM, with > > 1.6 versions of River jars, to run it. That can be done on a gradual, > machine-by-machine basis. > > The second step is to replace each program installation with its JVM 1.6 > > version, again on a machine-by-machine basis. During this phase, there > will be times when a 1.5 application needs to run a proxy that needs > 1.6, and solves the problem by spawning a 1.6 JVM to run it. > > At the end of the second step the system is fully 1.6, and the 1.5 JVM > and libraries can be uninstalled. > > If a service is implemented on multiple servers, and the servers are > updated at different times, the service remains continuously available. > > Does this make any sense? > > Patricia
