Journey’s End: Collection and Reduction in the Stream API

For streams to do useful work, they must end in a terminal operation. Most often that will be a collector, a new kind of operation invented for the Streams API. To use streams effectively, you need to understand how collectors work, what predefined collectors are available, and the factors that affect collector performance. This deep dive into the Collectors API explores the many predefined collectors and how to combine them for added power. You’ll do practical work, learning how to choose the right composition of collectors to solve practical programming problems. And you’ll see the difference between collection and reduction, how to recognize when you need to write your own collector, and the principles and rules for doing that.