Hi Hanadkat,
ORE is a suite of libraries that can be used to build any application you like, including an “OnDemand” server, however out of the box the only application available is the command line executable ore.exe. ORE does not have any web services or a RESTful api.
It is a C++ library and executable, so if you want to call it form Java then you could look at JNI, but it’s probably easier if you wrote out XML from java and then invoked ore.exe as a separate process, it depends on your application really.
Regards,
Niall.