code: public void notifyMonitors(ProcessInstance processInstance, String event) {
          TransactionWrapper transaction = null;
          try {
              transaction = startTransaction();
              engineImpl.notifyMonitors(processInstance, event);
          }
          catch (Exception ex) {
              // do not stop processing due to notification failure
              LoggerUtil.getStandardLogger().severeException(ex.getMessage(), ex);
          }
          finally {
              try {
                  stopTransaction(transaction);
              }
              catch (DataAccessException ex) {
                  LoggerUtil.getStandardLogger().severeException(ex.getMessage(), ex);
              }
          }
      }
docs: Notify registered ProcessMonitors.