private static final HashMap<Long, XXX> sCache = new HashMap<Long, XXX>();private static int sId = -1;public static void initAlbumArtCache() {  try {    //。。。    if (id != sId) {      clearCache();      sId = id;     }  } catch (RemoteException e) {    e.printStackTrace();  }}public static void clearCache() {  synchronized(sCache) {    sCache.clear();  }}public static XXX getCachedXXX(long Index, BitmapDrawable defaultBitmap) {  XXX d = null;  synchronized(sCache) {    d = sCache.get(Index);  }  if (d == null) {    //。。。    synchronized(sArtCache) {      // the cache may have changed since we checked      XXX value = sCache.get(Index);      if (value == null) {        sCache.put(Index, d);      } else {        d = value;      }    }  }  return d;}