code: public static LogFactory get() {
  		if (null == currentLogFactory) {
  			synchronized (lock) {
  				if (null == currentLogFactory) {
  					currentLogFactory = LogFactory.create();
  				}
  			}
  		}
  		return currentLogFactory;
  	}
docs: 获取单例日志工厂类，如果不存在创建之
  
  @return 当前使用的日志工厂