Extending Functional Pipeline with Gatherers by Venkat Subramaniam

We've had the ability to extend the terminal operation of a functional pipeline from the day one, thanks to the Collectors interface and the collect method. However, until recently we had no way to extend the intermediate steps of the functional pipeline. Why would we want to do that anyways, one may wonder. Aren't the built-in functions that make up the pipeline sufficient, one may ask. In this deep dive we will first explore the need to extend the functional pipeline. Then we will discuss what the new gatherer method and the Gatherers interface bring along. We will discuss the different types of Gatherers, when to use the different options, and provide recommendations as to which flavor to choose.