The code in this chapter will use the features defined in lambda leftovers (JEP 302), which has yet to be targeted for a JDK release version. To experiment with the code, you can clone the relevant repository.

All of the code in this chapter can be accessed at https://github.com/PacktPublishing/Java-11-and-12-New-Features.

Let's get started by understanding why would you need to mark unused lambda parameters.