public void registerLogHandler(LogHandler ht) {
        if (hasBeenShutDown.get()) {
            throw new IllegalStateException("Tried to register LogHandler on LogDispatcher which was shut down");
        }

        synchronized (this) {
            if (handlers.contains(ht)) {
                log.warning("LogHandler was already registered: " + ht);
                return;
            }
            handlers.add(ht);
        }

        if ((ht instanceof Thread) && (! ((Thread) ht).isAlive())) {
            ((Thread) ht).start();
        }

        log.fine("Added (and possibly started) LogHandler " + ht);
    }
Register handler thread with the dispatcher.  If the handler
thread has already been registered, we log a warning and
just do nothing.
<p>
If the thread is not alive it will be start()'ed.
logserver/src/main/java/com/yahoo/logserver/LogDispatcher.java