experimentalstuff.rm package,
this set of classes allows for defining and managing various
kinds of resources. The first release of the RM API will
have the CPU time and network resources management implemented.
But one can do much more - in particular, its possible to define
middleware- and application-specific resources. The initial
design of the RM API has been described
here.
We have also
written a report
on J2EE-related experiments
with the RM API. Since this API is used as a starting point
for the JSR 284, I'm encouraging anyone interested in the
topic of managing resources for Java programs to take a look at it.
Be warned, though: it will keep evolving.
The second major enhancement will be experimental extensions for clustering. They add clustering capabilities to the world of isolates (e.g., one can create them remotely) and to the RM API (e.g., one can control resource consumption of remote isolates). Quite neat. Really. We're trying to make cluster programming as easy as possible. Users' feedback will be invaluable to make sure we're heading in the useful direction. We've got just one public report on the use of cluster extensions; more to come.
MVM automatically virtualizes mutable state of Java classes. But how about static data of core native libraries? To demonstrate that's it's not so difficult to make a non-trivial and in a large part native subsystem of the Java HotSpot Virtual Machine multi-tasking friendly we've modified the XToolkit. The end effect is that multiple isolates will be able to execute AWT code without unwanted interference through the associated native libraries. Special thanks to our Geneva friends for taking care of this one.
We have also been working on the internal improvements to the MVM. The users will note faster start-up time and better overall performance of applications executed in MVM.
We're planning to bundle the above extensions into one code drop within the next several weeks. Further on the horizon is a port to the x86 plaform (Solaris and Linux). ]]>
MVM is a research modification of Sun's implementation of J2SE 5.0. In particular, it implements the second Public Review version of the JSR 121, also known as the Application Isolation API. This API adds the analog of a traditional operating system's address space abstraction (the Isolate class) to the Java Platform, thereby endowing it with a principled and easily used process model.
MVM has already proven itself in the CLDC space and now our team at the Sun Microsystems Laboratories is looking into ways MVM can improve J2SE and J2EE. People interested in the scalability of the Java platform will find MVM's start-up time and memory footprint reductions to be its most interesting aspects. Other users are likely to focus on (and hopefully like) the Application Isolation API, which in turn enables other technologies, leading to a more complete and programmable Java platform.
We plan to improve on this initial release. We will add a resource management facility, a clustering API, and a service management API and will update the Application Isolation API when its standardization is complete. Work on removing some of the current limitations, and tuning the implementation is also underway.
We are very interested in feedback and suggestions - please share your thoughts with us. Please note that you'll need to get the JDK Researcher role to be able to download MVM. ]]>