protobuf-rpc-pro is a Java developer library that provides an RPC layer for Google's Protocol Buffer services. It builds upon Netty for low-level NIO. Features include bidirectional RPC calls from client to server and from server to client. The client and server are equal communicating peers. TCP connection re-use / keep-alive, SSL encryption support, RPC call cancellation, timeout and a pluggable logging facility logging RPC call data in Protocol Buffer format are included.
hotpotato (or hptt, for short) is a high performance and throughput oriented HTTP client Java library, with support for HTTP 1.1 pipelining. It was developed mostly towards server-side usage, where speed and low resource usage are the key factors, but it can be used to build client applications as well. Built on top of Netty and designed for high concurrency scenarios where multiple threads can use the same instance of a client without any worries for external or internal synchronization, hotpotato helps you reduce initialization and/or preparation times and resource squandering. Among many small optimizations, connections are reused whenever possible, which results in a severe reduction of total request execution times by cutting connection establishment overhead.