.jengine
can be used to detect whether the engine was started
or to start the engine.
Before any callbacks from Java into R can be performed, the Java
callback engine must be initialized, loading Java/R Interface
(JRI). If JRI was not started and start
is set to TRUE
then .jengine
will load necessary classes and start
it.
Note that JRI is an optional part of rJava and requires R shared
library at the moment. By default rJava will continue with
installation even if JRI cannot be built.