title: How to optimize the implementation of java.util.Stream ? abstract: The Stream API is one of the newly introduced API in Java 8 that allows to use lambda to specify data transformations on collection elements. The first part of this talk will show what are the problems of the current implementations by explaining how the VM works and optimizes lambda calls. The second part will introduce different tips and tricks either inside the VM or in the JDK that can be used to improve the Stream pipeline implementation. Rémi