code: public synchronized void startAutoRollover() {
          // TODO: If java.util.Timer class is available, use it instead of
          // creating a thread each time.
          if (mRolloverThread == null) {
              mRolloverThread = new Thread(new AutoRollover(this), nextName());
              mRolloverThread.setDaemon(true);
              mRolloverThread.start();
          }
      }
docs: Starts up a thread that automatically rolls the underlying OutputStream
  at the beginning of the interval, even if no output is written.