One of the requested additions to Java that is currently under review is the addition of Orthogonal Persistance to the language. Basicaly this means that the the entire system, including all data and information about execution state can be wriitten to persistent storage such as a hard disk. This means that when you stop the system it can restart from exactly where it left off. It's something we were working on a while ago as part of the JOS system. The current proposal has it's foundations in PJama, an orthogonally persistant system for Java written by SunLabs. For a more general look at OP, have a look at Grasshopper.