> > A principal difference between RDDs and DataFrames/Datasets is that the > latter have a schema associated to them. This means that they support only > certain types (primitives, case classes and more) and that they are > uniform, whereas RDDs can contain any serializable object and must not > necessarily be uniform. These properties make it possible to generate very > efficient serialization and other optimizations that cannot be achieved > with plain RDDs. >
You can use Encoder.kryo() as well to serialize arbitrary objects, just like with RDDs.
