Through this chapter, you learned the basics of big data and its characteristics. You also learned about various NoSQL databases and their categories. The concepts of MapReduce, Hadoop, and Hadoop Distributed File System with a Java program were also covered. We completed this chapter with an understanding of distributed computing for big data and reviewed the architecture of Apache ZooKeeper for distributed computing.

In the next chapter, we will discuss essential testing, debugging, and troubleshooting aspects of Java-based distributed applications.