Mastering Concurrency Programming with Java 8

Chapter 7. Processing Massive Datasets with Parallel Streams – The Map and Reduce Model

Undoubtedly, the most important innovations introduced in Java 8 are lambda expressions and stream API. A stream is a sequence of elements that can be processed in a sequential or parallel way. We can transform the stream applying the intermediate operations and then perform a final computation to get the desired result (a list, an array, a number, and so on). In this chapter, we will cover the following topics:

• An introduction to streams
• The first example – a numerical summarization application
• The second example – an information retrieval search tool

An introduction to streams

A stream is a sequence of data (it is not a data structure) that allows you to apply ...