Explore the paradigm shift in reactive programming and its impact on application design and scalability in this keynote from Spring I/O 2016. Delve into the evolution of Java, the emergence of non-blocking runtimes, and the rise of reactive libraries like Reactor. Discover how Java 8 facilities and Reactive Streams are transforming application stacks. Learn about quality of service, end-to-end reactivity, and the role of Kafka Push in modern architectures. Gain insights into Spring Reactive projects and their potential for building full-stack reactive applications. Understand the motivations behind this major shift in programming models and its implications for writing and scaling applications in the future.