guava/src/com/google/common/util/concurrent/AtomicLongMap.java
public Map<K, Long> asMap() {
    Map<K, Long> result = asMap;
    return (result == null) ? asMap = createAsMap() : result;
  }
public Map<K, Long> asMap() {
    Map<K, Long> result = asMap;
    return (result == null) ? asMap = createAsMap() : result;
  }
Returns a live, read-only view of the map backing this {@code AtomicLongMap}.