Quick insight of Spring Reactor

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In this Spring Reactor blog, we will learn how we can get started with reactive behaviour and start producing and consuming messages in the same application itself.

What is Spring Reactor

Reactor, as mentioned by Spring itself, is a core component of JVM non-compliant applications which, on modest hardware, makes it possible to process more than 15,000,000 events per second with a non-stop Dispatcher. As it sounds, the Reactor framework is based on the Reactor design pattern.

Reactor in JVM

The most important thing about Spring Reactor is the level of inaccessibility of this framework that provides a Java Developer who develops applications using Spring. This release makes using our application performance much easier. Let’s start with a sample project to see how we can apply this framework in a situation that is close to real application. The reactor project also supports uninterruptible process communication (IPC) with reactor-ipc components but its discussion is out of syllabus.

Reactive Programming Promotes

  • Asynchronous
  • Non-blocking
  • Event driven Architecture

Feature of Spring Reactor

  • Asynchronous and Non-Blocking for I/O operations
  • Backpressure saving subscribers from drowning
  • Handle a large volume of concurrent requests coming from a single or multiple clients.
  • The Performance can be improve using the reactor stream.

Reactor Pattern

The reactor pattern is a single application of event-driven structures. In simple terms, it uses a one-series event loop that prevents events from releasing resources and sending them to associated holders with callbacks.

There is no need to block I / O, as long as event managers and callers are register to take care of it. Events refer to situations such as new incoming connections, readable readings, ready-to-write, etc. Those holders / callbacks may use thread pool in multi-core areas.This pattern separates the application level code from the reactor reuse.

There are two key participants in the formation of the Reactor pattern:

  • Reactor
  • Handlers


The Reactor operates in a separate series, and its function is to respond to IO events by sending the function to the appropriate host. It is like a telephone operator in a company who answers calls from customers and then passes the line to the appropriate contact.


The manager does the actual work that needs to be done with an I / O event, similar to a real company official the client wants to talk to. The reactor responds to I / O events by sending the appropriate holder. Holders perform non-stop actions.


In this block we covered the basics of spring reactor with its features and reactor patterns. With the help of reactive programming we can move away from the thread per request model and can handle more requests with a low number of threads. If you want to get started with spring reactor you can refer https://projectreactor.io/




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