code: public static Log getLog(Class<?> source) {
  		synchronized (logs) {
  			Log log = new DeferredLog();
  			logs.put(log, source);
  			return log;
  		}
  	}
docs: Get a {@link Log} instance for the specified source that will be automatically
  {@link DeferredLog#switchTo(Class) switched} when the
  {@link ApplicationPreparedEvent context is prepared}.
  @param source the source for logging
  @return a {@link DeferredLog} instance