public Object callAndWait( byte channel, short objId, short procId, Object... args ) {
        return rpc.callAndWait(channel, objId, procId, args);
    }
Performs a synchronous call on the server against the specified
 object using the specified procedure ID.  Both inbound and outbound
 communication is done on the specified channel.
jme3-networking/src/main/java/com/jme3/network/service/rpc/RpcClientService.java