Your One‑Stop Spring Guide: Boot, Cloud, and Security Resources

Compiled index of Spring ecosystem articles covering Spring Boot, Spring Cloud, Spring Security, and OAuth2, focusing on practical implementation details.

Spring Boot

Fundamental concepts and common patterns.

Quick start guide using Spring Initializr and IntelliJ.

Creating web applications with embedded Tomcat, RESTful APIs, and unit testing with Spring Test.

Unified exception handling using @ControllerAdvice and custom error responses.

Generating Swagger2 API documentation via springfox‑swagger2.

Sending email with JavaMailSender.

Customizing the startup banner.

Dynamic log level adjustment at runtime (Spring Boot 1.5.x).

Advanced topics

Auto‑configuration mechanism: how Spring Boot selects starters, pros/cons, and how to disable or replace defaults.

Rate limiting strategies (Bucket4j, Redis token bucket) and integration with filters.

Externalized configuration: hierarchy of application.yml / application.properties, profile‑specific files, and @ConfigurationProperties binding.

Memory management guidelines for Spring Boot & Spring Cloud (heap sizing, GC tuning, actuator metrics).

Running Spring Boot as a background service (systemd unit files, nohup, Docker).

Deploying to Heroku (Procfile, Maven/Gradle buildpacks).

Actuator monitoring endpoints: health, metrics, env, and custom endpoints; using /info to expose Git commit information.

Real‑time monitoring stack: Actuator → Jolokia → Grafana dashboards.

Spring Cloud

Microservice infrastructure basics.

Service registration and discovery with Eureka and Consul.

Client‑side load balancing using Ribbon and declarative HTTP clients with Feign.

Distributed configuration with Spring Cloud Config Server and client bootstrap.

Fault tolerance with Hystrix: circuit breaker, thread/semaphore isolation, request caching, and fallback methods.

Hystrix dashboard and Turbine aggregation for multiple instances.

API gateway fundamentals with Spring Cloud Gateway (routing, predicates, filters).

Common pitfalls: random port allocation, health‑check endpoints, Feign‑Hystrix exception handling, Config Server cache refresh.

Contract testing using Spring Cloud Contract (consumer‑driven contracts).

Advanced deployment patterns: canary releases, gray deployments, A/B testing, rolling upgrades.

Spring Cloud Zuul (API Gateway)

Dynamic routing configuration via Zuul routes and service discovery.

Handling cookies and redirects in pre‑ and post‑filters.

Implementation of core Zuul filters (pre, route, post, error) and custom filter development.

Unified exception handling across Zuul filters.

Eager‑load mode for route definitions.

Retry mechanism configuration (maxAttempts, backoff).

Spring Security

Architecture overview: security filter chain, AuthenticationManager, and ProviderManager.

Core configuration using HttpSecurity DSL, method security annotations, and password encoding.

Source analysis of UsernamePasswordAuthenticationFilter and other default filters.

Custom authentication example: IP‑based login implementation.

Spring Security OAuth2

Building an OAuth2 authorization server from scratch (client registration, token endpoint, JWT signing).

Resource server configuration: securing REST endpoints with @EnableResourceServer and token validation.

Refresh token flow and token revocation.