code: public String getId(int iid) {
  		if (iid < 0 || iid > loadCounter) {
  			System.out.println("Internal id " + iid + " is out of range!");
  			return null;
  		}
  		DatabaseEntry key = new DatabaseEntry();
  		IntegerBinding.intToEntry(iid, key);
  		DatabaseEntry data = new DatabaseEntry();
  		if ((iidToIdDB.get(null, key, data, null) == OperationStatus.SUCCESS)) {
  			return StringBinding.entryToString(data);
  		} else {
  			System.out.println("Internal id " + iid + " is in range but id was not found..");
  			System.out.println("Index is probably corrupted");
  			System.exit(0);
  			return null;
  		}
  	}
docs: Returns the id of the vector which was assigned the given internal id or null if the internal id does
  not exist. Accesses the BDB store!
  
  @param iid
  The internal id of the vector
  @return The id mapped to the given internal id or null if the internal id does not exist