private void dropUnregisteredIndices() { final Set<String> indicesToDrop = new HashSet<String>( myPreviouslyRegistered != null ? myPreviouslyRegistered.registeredIndices : Collections.<String>emptyList()); for (ID<?, ?> key : myIndices.keySet()) { indicesToDrop.remove(key.toString()); } for (String s : indicesToDrop) { FileUtil.delete(IndexInfrastructure.getIndexRootDir(ID.create(s))); } }