The log you perform in your code should be entirely managed by your code, without Lightstreamer involvement
(although the java remote SDK also provides a very simple logging interface).
For instance if your "logger" object is obtained with slf4j, you should provide a suitable slf4j implementation and configuration.

However, Giuseppe's advise was to log the startup phase of the process, when the process tries to establish a connection with Lightstreamer Server, since there is no evidence of such connection.
As log as the remote adapter process fails to connect, it won't receive any invocation of "subscribe", hence it is correct that you can't see this log.