A simple socket based RPC transport layer for protocol buffers. Implements an asynchronous RpcChannel. Look at the example for how to implement a simple service.
During another project I needed fast RPCs for Android phones. In the beginning I used jsonrpc4j and Jetty which are a wonderful pieces of software, but unfortunately can be really slow.
If you need a lightweight RPC mechanism you may find this useful.
Because I want to keep this library small (and also because I'm lazy) I only support asynchronous RPCs. You can simulate synchronous calls by waiting for each RPC to complete.