code: public final synchronized boolean reserveId(long id, Object obj)
  	{
  		if (tc.isEntryEnabled()) Tr.entry(tc, "reserveId", new Object[] {new Long(id), obj});
  
  		boolean reserved = false;
  
  		// The id can only be reserved if it
  		// isn't already in the map
  		if (_idMap.get(id) == null)
  		{
  			_idMap.put(id, obj);
  			reserved = true;
  		}
      
  		if (tc.isEntryEnabled()) Tr.exit(tc, "reserveId", new Boolean(reserved));
  
  		return reserved;
  	}
docs: Reserve the given id and associate it with
  the given object. This method should be used
  during recovery when there is a requirement to
  create a new object with a specific id rather than
  the one that is next available.
  
  @return true if the id was successfully reserved.
  @param id The value of the id to be reserved
  @param obj The object that requires the id