The new Lambda feature of Java 8 and onwards is discussed in great detail in this course. Since functional interfaces are a prerequisite of understanding lambdas, they are discussed and explained here as well. Method references, which are shorthand notations for lambda expressions, are explained in this course as well. Exercises and their solutions round off the course, so be prepared and ready to get your hands dirty!
The course is completely free (yes, FREE!).
The course is originally designed as an exam study guide for the 1z0-817 Oracle Certified Java SE 11 upgrade exam.
But one can learn the topics (like lambdas, streams, modules, ...) separately, without intending to take the exam.
The topics are discussed in great detail sometimes, so be prepared to get some serious information and a feel like for what exam preparation looks like for certified programmers!
The exam consists of 10 exam topics, lambdas (this course right here) being only one of them.
Lambdas, Streams and Modules will be uploaded here. The complete course can be seen on Boras Developer Academy. So see you there!