Should LinkedList be deprecated? This question might look like one more useless troll if had not been asked by Stuart Marks, Java/JDK/OpenJDK developer at Oracle, a true expert of the subject, currently working on the evolutions of the Collection Framework for Java 9 and beyond. Followed a long thread with many fine contributions that we will see. It turns out that answering this question takes us for quite a long journey, from algorithms and their complexity to memory footprint and CPU caches usage. We will show how to evaluate the performance and the main data structures in the Collection Framework: ArayList, LinkedList, HashSet, HashMap using JMH, now the JDK standard for microbenchmarking. We will also see alternative Collection implementations. This talk will cover the notions of pointer chasing, CPU caches, and what Java 9 brings for the Collection Framework. Lastly, we will show how to implement collections and hashmaps with lambda expressions. José Paumard 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 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. [SBX-4851]