code: private void addClientId(String clientId) {
          //Sometimes the client Id will be null. For instance in the case QueueConnectionFactory, there is no default client Id specified in metatype.xml.
          if (clientId == null)
              return; //do nothing
  
          ConcurrentHashMap<String, Integer> clientIdTable = JmsFactoryFactoryImpl.getClientIdTable();
  
          if (clientIdTable.containsKey(clientId)) {
              clientIdTable.put(clientId, clientIdTable.get(clientId).intValue() + 1);
          } else {
              clientIdTable.put(clientId, 1);
          }
  
      }
docs: If there is no entry for the given Client Id in the "clientIdTable", then add it with count as "1".
  If its already exists then just increment the counter value by "1".
  
  @param clientId