Lambdas are the main feature introduced with Java 8, but the biggest part of Java developers are still not very familliar with the most common functional idioms and patterns. The purpose of this talk is presenting with practical examples concepts like high-order functions, currying, functions composition, persistent data structures, lazy evaluation, recursion, trampolines and monoids showing how to implement them in Java and how thinking functionally can help us to design and develop more readable, reusable, performant, parallelizable and in a word better, code.