Rserve

Rserve is a free and open-source TCP/IP server for developers who want to integrate various features of R from other programming languages into their software applications without having to actually initialize R or create links to the R library.
It contains client-side tools that allow C, C++, PHP and Java apps to initialize connections. Support is available for user authentication, file transfers, and remote connections. The connections are made in distinct workspaces and working folders.
Under normal circumstances, its necessary to integrate the R backend into projects for generating statistical models or plots, for example. However, Rserver can be seamlessly integrated through this Java code: RConnection c = new RConnection(); double d[] = c.eval("rnorm(10)").asDoubles();
In this code, d has 10 random samples from the N(0,1) distribution if the local computer is running Rserve. Its possible to create the RConnection only once to execute additional commands, but each thread has to be associated with a distinct connection object unless the synchronization is explicitly defined.
The server is accompanied by three client frameworks, REngine Java client (allows JDK 1.4 or higher access to the server), JRclient (basic interface from C++ to the server) and R client, as well as third-party clients, namely Python: pyRserve, .NET/CLI: RserveCLI, C#: RserveLink, and Ruby: rserve-client.
Complete documentation, examples and other information are available on the developers website.System requirementsR for Windows 1.5.0 or higher