title: How to declare an empty dataset in Spark?
body: <p>I am new in Spark and Spark dataset. I was trying to declare an empty dataset using <code>emptyDataset</code> but it was asking for <code>org.apache.spark.sql.Encoder</code>. The data type I am using for the dataset is an object of <code>case class Tp(s1: String, s2: String, s3: String)</code>.</p>