code: public final void error(Object message, Throwable t) {
          if (isLevelEnabled(LOG_LEVEL_ERROR)) {
              log(LOG_LEVEL_ERROR, message, t);
          }
      }
docs: Logs a message with <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_ERROR</code>.
  
  @param message to log
  @param t       log this cause
  
  @see Log#error(Object, Throwable)