Collectors in the wild! by José Paumard

The Collector API has been added to the JDK 8, and was left in the shadow of the Stream API. It is quite logical, since a collector is made to consume the elements of a stream: no Stream, no Collector. We have a set of ready to use, very powerful collectors in the Collectors class: toList and groupingBy, to name a few. Those two facts hide the collector model to process data, and how powerful and efficient is this API. This in depth talk is all about collectors: those available, because we need to know them, those that we can create, those we had no idea they could be created, and the others, as there is in fact no limit to what can be done with this API. The concept of downstream collector will be used to show how we can write entire data processing pipelines using collectors only, and pass them as parameters to other pipelines. We will be careful about keeping a high level of readability in our code, and also talk about performances. This talks is composed of slides and live coding on simple and complex examples. # José Paumard José is an assistant professor at the Institut Galilée (Université Paris 13) and a PhD in applied mathematics from the ENS de Cachan. He has discovered the Java language in 1995, and has been teaching the Java technologies at the university since 1998. José is also a Java Champion and Java Rockstar. José has also been working as an independant for numerous companies, in a variety of areas. He is a well known Java / Java EE / Software Craftsmanship expert and trainer. He also publishes "Java le soir", a technical blog in french (http://blog.paumard.org/), with about 750 pages of courses about Java / JEE in open access.