Discover how circuit breakers help prevent cascading failures, improve system stability, and protect your services from repeated errors. By the end of this chapter, you will understand the core concepts and practical benefits of using circuit breakers in your Spring projects.

What Is a Circuit Breaker?

A circuit breaker is a design pattern that helps your application handle failures in external systems, such as databases or web services. When a system or service stops working, a circuit breaker can detect the problem and temporarily stop requests to that service. This prevents your application from making repeated, failing calls that could slow down or crash your system.

Why Circuit Breakers Matter in Spring Applications

Spring applications often rely on other services, APIs, or databases. If one of these dependencies becomes slow or unavailable, your application might also slow down or fail. Circuit breakers help by:

• Detecting repeated failures in a dependent service;
• Stopping requests to the failing service for a period of time;
• Allowing the service to recover before trying again.

This keeps your application responsive, even when some parts of your system are having problems.

Preventing Cascading Failures

A cascading failure happens when a problem in one service causes failures in other connected systems. Circuit breakers prevent this by quickly identifying failing services and blocking further calls to them. This protects the rest of your application from being overwhelmed by errors and helps keep your system stable.