public synchronized void commit() {
        if (tempList.isEmpty())
            return;
        if (!tempList.isEmpty()) {
            for (KV<String, T> tuple : tempList) {
                persistentTable.put(tuple.getKey(), tuple.getValue());
            }
            tempList.clear();
        }
    }
DEPRECATED: may cause OutOfMemoryError on large crawls.

@return
ache/src/main/java/achecrawler/util/persistence/PersistentHashtable.java