JavaOne: TS-7159: Java Platform Clustering: Present and Future

Research goal is transparent extension of Java programming model and facilities to a clustered environment. More for performance, than failure issues.

Design Approaches:

• Cluster-aware JVMs (potentially optimal [close to hardware], but loses portability)
• Compile to cluster-enabled layer (ex. DSM; good performance, but lose portability and impedence mismatch)
• Systems using standard JVM (transforms at code or bytecode level). lose performance but get portability

Compile to DSM:

• Hyperion - compiles to C code that is DSM aware
• Jackal - violates Java memory model

Cluster-aware JVM software:

• Java/DSM (Rice, 1997) - piggybacks on existing DSM, no JIT
• cJVM (aka trusted JVM) (IBM, 1999) - proxy objects for non-local access (smart), no JIT
• Kaffemik (Trinity college, 2001) - based on kaffe VM, scalable coherent interface, JIT
• Jessica2 (2002) - JIT support, thread migration
• dJVM (2002) - based on Jikes

Systems based on standard JVM:

• JavaParty (1997) - pre-processor + runtime compiles to RMI. Requires langauage change
• JSDM (2001) - supports SPMD apps, not full Java technology
• JavaSplit - bytecode transformation, integrated custom DSM
• J/Orchestra - application partitioning, bytecode transformation

The executive summary is that there is some work going on to make Java cluster-aware at the VM level. I'm not sure why Jini wasn't mentioned more, since it seems like a natural fit for clusters. If I ever need to do some clustering, I can check in on the above projects to see if there is a fit.