block()/blockFirst()/blockLast() Are Blocking — Here's Why
WebClient.block() throws 'are blocking, which is not supported' and it looks like a Netty bug. It isn't. Here's the real mechanism, and the failure it's hiding.
spring-boot
10 PostsSpring Boot 4: @JsonComponent Silently Stops Working
Upgraded to Spring Boot 4 and your @JsonComponent went quiet? Jackson 3 took the HTTP layer without telling you. Here's the exact mechanism and the real fix.
Binding to target ... failed: two bugs, one identical banner
BindValidationException and UnboundConfigurationPropertiesException print the exact same Spring Boot startup banner. Here's how to tell which broke your app.
APPLICATION FAILED TO START, and When You Don't Get It
Spring Boot's failure banner only shows up when one of ~40 built-in analyzers recognizes your exception. Here's the catalog, and what prints when none do.
TestRestTemplate's NoSuchBeanDefinitionException in Spring Boot 4
Boot 4 quietly stopped auto-wiring TestRestTemplate and MockMvc in @SpringBootTest, and the @MockBean-to-@MockitoBean rename hides a sneakier trap of its own.
Mastering Spring Boot: Building Production-Ready Microservices
Spring Boot has revolutionized Java application development by eliminating boilerplate configuration and providing a streamlined approach to building production-ready
Spring Boot Hello World Tutorial with Lombok and H2 Database – Quick Start for Beginners
Learn how to create a Hello World Spring Boot application using Lombok for cleaner code and the H2 in-memory database for rapid development. This step-by-step guide includes annotations, project setup, REST API, H2 console access, and more to kickstart your Spring Boot journey.
Spring vs. Spring Boot: Key Differences Developers Must Know
Spring or Spring Boot? One gives you full control, the other gets you up and running fast. If you're building Java apps, knowing the difference isn't optional—it’s critical. Here’s the breakdown every dev should read.
NoSuchBeanDefinitionException: The Most Common Spring Bean Error
Learn how to fix NoSuchBeanDefinitionException in Spring Boot with clear examples and best practices for dependency injection, package scanning, and bean registration.
BeanCurrentlyInCreationException: Circular Dependencies in Spring
Spring Boot’s DI can backfire with the dreaded BeanCurrentlyInCreationException, signaling an unresolvable circular dependency. Learn why cycles occur, how they breach SOLID principles, and three fixes—refactor to break loops, use @Lazy injection, and static @Bean factory methods—to restore startup.