References
Here are some links you can refer to for more information:
https://databricks.com/blog/2016/07/14/a-tale-of-three-apache-spark-apis-rdds-dataframes-and-datasets.html, which provides information on three Apache Spark APIs, RDDs, DataFrames, and Datasets; when to use them; and why to use them.
https://databricks.com/blog/2016/05/11/spark-2-0-technical-preview-easier-faster-and-smarter.html