The source code for this article can be found on Github.

The Resilience4j circuit breaker by default considers any exception thrown inside of the Supplier as a failure. If over 50% of the calls are failures and the rolling window max size is met, then it will prevent any future calls from going through.

The source code for what follows can be found on Github.

The circuit breaker pattern, popularized by Netflix [using Hystrix], exists for a couple of reasons, the most prominent being that it reduces load on a downstream service when it is not responding properly [presumably because it’s under duress]. By wrapping operations that might fail and get overloaded in a circuit breaker, we can prematurely prevent cascading failure and stop overloading those services.

The source code for what follows can be found on Github.

When you’re working with distributed systems, it is often the case that some clones of a service running can be slow to respond, while still others are functioning perfectly normally. Therefore, when you just hit a load balancer and the load balancer chooses a backend, it can sometimes be beneficial to retry the request. Other things like periodic and small database stalls or random GC stop-the-worlds are examples where retries can smooth the experience for the client of your service.