Spring Boot Articles

Spring Boot Observability: Micrometer Metrics and Tracing

Spring Boot's observability, powered by Micrometer, can feel like magic until you realize it's just about making the invisible visible.

2 min read

Spring Boot OpenTelemetry Tracing: Auto-Instrument Setup

Spring Boot's auto-instrumentation for OpenTelemetry tracing doesn't actually add tracing to your application; it enables existing, latent tracing capab.

2 min read

Profile Spring Boot Performance: JFR and Async-Profiler

Profile Spring Boot Performance: JFR and Async-Profiler — practical guide covering spring-boot setup, configuration, and troubleshooting with real-world...

2 min read

Spring Boot R2DBC: Reactive Database Access Setup

Spring Boot R2DBC setup is less about connecting to a database and more about managing a network of concurrent, non-blocking I/O operations.

2 min read

Spring Boot Rate Limiting: Bucket4j and Redis Setup

Spring Boot applications often need to control the rate at which clients can access them, and Bucket4j paired with Redis is a robust way to handle this.

4 min read

Spring Boot REST Client: Feign vs WebClient Comparison

Feign and WebClient are both popular choices for building REST clients in Spring Boot, but they tackle the problem from fundamentally different angles, .

2 min read

Spring Boot Scheduling with Distributed Lock: ShedLock

ShedLock doesn't actually prevent multiple instances from executing a scheduled task; it ensures only one instance acquires the lock for that task.

2 min read

Spring Boot Security CSRF and CORS: Configure Both

Spring Boot Security's CSRF and CORS are often configured together, but they solve fundamentally different problems, and their interaction can be a sour.

4 min read

Spring Boot Security Hardening Checklist

Spring Boot Security Hardening Checklist Spring Boot Security, by default, is not secure enough for production environments.

4 min read

Spring Boot JWT and OAuth2 in Production: Full Config

Spring Boot JWT and OAuth2 in production: Full Config The most surprising thing about JWT and OAuth2 in production is that they're often implemented as .

3 min read

Spring Boot Startup Time Optimization: Lazy Init and AOT

Spring Boot applications can sometimes take a surprisingly long time to start, and it's often because the framework is doing a lot of work before your a.

2 min read

Spring Boot Test Slices: @WebMvcTest and @MockBean

@WebMvcTest and @MockBean in Spring Boot are your best friends for unit testing your web layer without the overhead of a full application context.

2 min read

Spring Boot Transaction Management: @Transactional Deep Dive

Spring Boot's @Transactional annotation isn't just a magic bullet for database operations; it's a powerful, yet often misunderstood, tool that can lead .

2 min read

Spring Boot Validation: Custom Constraint Annotations

Spring Boot's validation framework is a powerful tool, but the real magic happens when you go beyond the built-in constraints and create your own.

3 min read

Spring Boot WebFlux vs MVC: Choose the Right Model

Spring WebFlux and Spring MVC are both powerful frameworks for building web applications in Spring, but they approach concurrency and I/O very different.

4 min read

Spring Boot Zero-Downtime Rolling Deploy on Kubernetes

Spring Boot applications on Kubernetes can achieve zero-downtime rolling deployments by carefully orchestrating the lifecycle of new and old pods.

3 min read

Fix Spring Boot MySQL Server Time Zone Unrecognized Error

Fix Spring Boot MySQL Server Time Zone Unrecognized Error — practical guide covering spring-boot setup, configuration, and troubleshooting with real-wor...

4 min read

Fix Spring Boot Detached Entity Passed to Persist Error

Fix Spring Boot Detached Entity Passed to Persist Error — The org.springframework.orm.jpa.JpaSystemException: org.hibernate.PersistentObjectException: d...

6 min read

Fix Spring Boot Eureka Server Not Found Error

The Eureka client is failing to register with the Eureka server because the server is not responding to client requests at the expected network address.

3 min read

Fix HikariPool Connection Not Available Timeout Error

Fix HikariPool Connection Not Available Timeout Error — The HikariPool.getConnection method is failing because the pool cannot acquire a new connection ...

4 min read

Fix Spring Boot Media Type Not Supported Error

The Content-Type header sent by your client is not recognized by the Spring Boot application's message converters, preventing it from deserializing your.

3 min read

Fix Spring Boot 404 No Message Available Error

This error means Spring Boot's DispatcherServlet tried to find a handler for your incoming request, couldn't find one, and then failed to find a default.

3 min read

Fix Spring Boot JPA Transaction Manager Config Error

Fix Spring Boot JPA Transaction Manager Config Error — The org.springframework.beans.factory.UnsatisfiedDependencyException means your Spring Boot appli...

3 min read

Fix Spring Boot Request Method Not Supported Error

The 5xx error you're seeing, "Request method 'GET' not supported," means your Spring Boot application received an HTTP GET request but the controller ha.

5 min read

Spring Boot 3 Virtual Threads: Project Loom Setup

Spring Boot 3's virtual threads, powered by Project Loom, fundamentally change how your application handles concurrency, allowing thousands of concurren.

3 min read

Spring Boot Actuator: Production-Ready Endpoints Setup

Spring Boot Actuator endpoints are enabled by default, but they're not automatically exposed externally in production, which is often a surprise for new.

2 min read

Spring Boot AOP Internals: Proxy and CGLIB Deep Dive

Spring's AOP proxying is actually two distinct mechanisms, and understanding which one is active is the key to debugging AOP issues.

2 min read

Spring Boot API Versioning: URI, Header, and Media Type

The most surprising thing about API versioning is that you don't have to version your API at all, at least not in the way most people think.

3 min read

Spring Boot Application Context Lifecycle Explained

The Spring Application Context is not a single, monolithic entity; it's a dynamic, multi-stage lifecycle that can be surprisingly complex, with beans be.

3 min read

Spring Boot Async Task Executor: Configure and Tune

Spring Boot's default AsyncTaskExecutor is a bit of a blunt instrument, and tuning it is crucial for anything beyond trivial applications.

4 min read

Spring Boot Auto-Configuration: How It Works Inside

Spring Boot's auto-configuration is a bit like a really good sous chef who anticipates what ingredients you'll need based on what you've already put in .

3 min read

Spring Boot Batch: Process Large Datasets Efficiently

Spring Batch doesn't actually process large datasets; it orchestrates the reading, processing, and writing of data in manageable chunks.

2 min read

Spring Boot Bean Lifecycle: Init, Inject, Destroy

Spring Boot's bean lifecycle is a lot more than just "create it, use it, throw it away. " Here's a simple Spring Boot application that demonstrates the .

4 min read

Spring Boot Caching: Redis and EhCache Configuration

Spring Boot's caching abstraction is surprisingly flexible, but its default behavior often hides the fact that you're not actually using Redis or EhCach.

3 min read

Spring Boot Circuit Breaker: Resilience4j Patterns

Resilience4j's circuit breaker doesn't just stop calls to a failing service; it actively learns from failures to decide when to let calls through again.

3 min read

Fix Spring Boot Class Loading Issues: Classpath Conflicts

The Spring Boot application failed to start because a critical class required for its operation could not be found, indicating a problem with how the ap.

4 min read

Spring Boot Conditional Beans: @ConditionalOn* Explained

Spring Boot's conditional beans let you surgically inject components into your application context only when specific criteria are met, but most develop.

2 min read

Spring Boot HikariCP Tuning: Connection Pool for Production

Spring Boot applications often struggle with database connection management, leading to performance bottlenecks and application instability under load.

3 min read

Build a Spring Boot Custom Starter: Auto-Configuration

Spring Boot starters are a powerful mechanism for packaging and distributing reusable configurations, but understanding how they actually inject those c.

2 min read

Spring Boot JPA vs JdbcTemplate: When to Use Each

Spring Boot JPA is often pitched as the "easy button" for database access, but the real magic is how it abstracts away tedious boilerplate, letting you .

2 min read

Spring Boot Docker: Layered JARs and Jib Builds

Spring Boot applications, when containerized with Jib, can be built into highly efficient, multi-layered Docker images by leveraging Spring Boot's "laye.

2 min read

Spring Boot Event-Driven Architecture: Application Events

Spring Boot's application events let components communicate asynchronously, but they're not magic — they still rely on a synchronous dispatcher under th.

3 min read

Spring Boot Event System: ApplicationEventPublisher Internals

The Spring Event system is often misunderstood as a simple observer pattern, but its true power lies in its ability to decouple components so thoroughly.

3 min read

Spring Boot Externalized Config: application.yml and Profiles

Spring Boot Externalized Config: application.yml and Profiles — practical guide covering spring-boot setup, configuration, and troubleshooting with real...

3 min read

Spring Boot Graceful Shutdown: Drain Requests on Stop

Spring Boot's graceful shutdown isn't about stopping gracefully; it's about preventing new requests from being processed while actively finishing the on.

3 min read

Spring Boot gRPC Production Setup: Server and Client

Spring Boot gRPC production setups often surprise people because they're less about the RPC framework itself and more about managing distributed system .

2 min read

Spring Boot Integration Test Patterns: @SpringBootTest

@SpringBootTest can be a black box if you don't know what's happening under the hood. Let's see what @SpringBootTest actually does when you run a test

2 min read

Spring Boot Senior Engineer Interview Questions

The most surprising thing about Spring Boot is that it’s less about new Spring features and more about opinionated defaults that make existing Spring fe.

2 min read

Fix Spring Boot JPA N+1 Problem: Fetch Joins and Batching

The N+1 problem in Spring Boot JPA occurs when your application makes one query to fetch a collection of parent entities, and then for each parent entit.

3 min read

Spring Boot Kafka Consumer and Producer: Setup Guide

Spring Boot makes setting up Kafka producers and consumers surprisingly straightforward, but the most counterintuitive aspect is how much of the underly.

3 min read

Deploy Spring Boot to Kubernetes: Helm and Probes

Helm charts are not just for packaging; they're the orchestrator for your Spring Boot application's life on Kubernetes, and probes are the sentinels tha.

3 min read

Spring Boot Microservices with Resilience4j: Circuit Breakers

Spring Boot microservices with Resilience4j Circuit Breakers: Circuit Breakers The most surprising thing about circuit breakers is that they don't actua.

3 min read

Migrate Spring Boot 2 to 3: Breaking Changes and Steps

Spring Boot 3 is a pretty big leap from Spring Boot 2, and it's not just a minor version bump. The core of the change is a shift to Java 17 as the basel.

4 min read

Spring Boot Module Structure: Package and Layer Best Practices

Spring Boot applications can grow complex quickly, and how you structure your code is often the difference between a maintainable project and a tangled .

3 min read

Spring Boot Multi-Tenancy: Schema and Database Strategies

Spring Boot's multi-tenancy, especially with schema and database strategies, is far more complex than just telling your app to talk to different databas.

3 min read

Spring Boot Native with GraalVM: Compile to Native Binary

Spring Boot Native lets you compile your Spring Boot applications into a native executable using GraalVM, ditching the JVM entirely for faster startup a.

3 min read

Spring Boot OAuth2 Resource Server: JWT Validation Setup

Spring Boot's OAuth2 Resource Server doesn't actually validate JWTs by default; it just blindly trusts them if they look like JWTs.

6 min read

Fix Spring Boot: Consider Defining a Bean of Type Error

Fix Spring Boot: Consider Defining a Bean of Type Error — The Consider defining a bean of type ... error means Spring's dependency injection container c...

4 min read

Fix Spring Boot: Consider Marking One Bean as @Primary

This error means Spring couldn't decide which implementation of an interface to inject because you have multiple candidates and didn't specify a prefere.

4 min read