In this chapter, you learned about the history of Bigdata and its dimensions and basic concepts of Hadoop and Spark. After that, you were introduced to RDD, and you learned the basic concepts of the Spark RDD model. Then, you learned about the various components of the Spark Ecosystem and the newer features of Spark 2.x.
As this book focuses on implementing Spark Applications in Java, in the next chapter, we will refresh the concepts of core Java and focus on the newer feature of Java 8, which will be leveraged while developing Spark Applications.