Iterator<Map.Entry<BlobKey, Integer>> entryIter = blobKeyReferenceCounters.entrySet().iterator();
while (entryIter.hasNext()) {
Map.Entry<BlobKey, Integer> entry = entryIter.next();
BlobKey key = entry.getKey();
int references = entry.getValue();
try {
if (references <= 0) {
blobService.delete(key);