The feature was added to RFA/Java 7.6.0 but the documentation was not updated to actually the detail how to use and configure the transport until 8.0.0.L2.

2.2.3 Features and Enhancements in 7.6.0

Multicast to ADS Connectivity
-----------------------------
This release adds a new connection type to allow many-to-many connectivity to an ADS that supports multicast. This connection type provides gap detection and recovery, message sequencing, and fault tolerant grouping of multicast configured ADSs. 
(This functionality requires ADS 2.6 or newer)

There is a new section 3.2.2 RSSL_MCAST_CONS Connection in the "Configuration and Logging Guide - Java Edition".

No examples have been updated with ADS multicast transport usage.

An equivalent UPA/Java update has not yet been published, version 8.0.0.L1 does not document the feature. It is documented that the JNI libraries are required for reliable multicast, and a present limitation of the ValueAdd watchlist library which is a dependency on EMA/Java:

6.1 UPA Java Edition Limitations and Known Issues

    - UPA Java Reactor does not include watchlist support.  This will be added
      in a subsequent releases.  As a result, UPA Java cannot support connectivity
      to a Multicast ADS using the Reliable UDP Multicast transport.  This will 
      be added after Reactor watchlist functionality is made available.

Hi Akechi,

The RFA Java APIs that support the ADS multicast connection are RFA Java 7.6 and RFA Java 8.0.

Please see more detail in the following documents:

• Section 2.2 Features of RFA in the RFA Java Developer guide document
• Section 3.2.2 RSSL_MAST_CONS in the RFA Java Config Logging document