sci rJava is a simple R-to-Java interface. It is comparable to the .C/.Call C interface. rJava provides a low-level bridge between R and Java (via JNI). In a sense the inverse of rJava is JRI (Java/R Interface) which provides the opposite direction - calling R from Java. JRI is now shipped as a part of the rJava package, although it still can be used as a separate entity (especially for development).