code: public void put(String identifier, ActiveConnectionRecord record) {
          synchronized (records) {
  
              // Get set of active connection records, creating if necessary
              Set<ActiveConnectionRecord> connections = records.get(identifier);
              if (connections == null) {
                  connections = Collections.synchronizedSet(Collections.newSetFromMap(new LinkedHashMap<ActiveConnectionRecord, Boolean>()));
                  records.put(identifier, connections);
              }
  
              // Add active connection
              connections.add(record);
  
          }
      }
docs: Stores the given connection record in the list of active connections
  associated with the object having the given identifier.
  
  @param identifier
  The identifier of the object being connected to.
  
  @param record
  The record associated with the active connection.