private final HashMap<Long, byte[]> overwriteBackup = new HashMap<Long, byte[]>();
private final ConcurrentLinkedQueue<Long> overwriteQueue = new ConcurrentLinkedQueue<Long>();
private final long size;
public PersistentMap(File dir, String filename, long size, int entries) throws IOException {
f = new FileMap(dir, filename, size, entries);
this.size = size;
}