Does spark support Apache Arrow

[Todd]

From the official site http://arrow.apache.org/, Apache Arrow is used for 
Columnar In-Memory storage. I have two quick questions:
1. Does spark support Apache Arrow?
2. When dataframe is cached in memory, the data are saved in columnar in-memory 
style. What is the relationship between this feature and Apache Arrow,that is,
when the data is in Apache Arrow format，does spark still need the effort to 
cache the dataframe in columnar in-memory?