static <A, B> B syncMapGet2(Map<A, B> map, A a) {
  if (map == null) null;
  synchronized(collectionMutex(map)) {
    ret map.get(a);
  }
}

static <A, B> B mapMethodLike syncMapGet2(A a, Map<A, B> map) {
  ret syncMapGet2(map, a);
}