Spring Boot Troubleshooting

Upgrading Java can provide performance, security, and feature benefits.But in real Spring Boot projects, a Java version upgrade often leads to startup failures. This guide explains why Spring Boot applications fail to start after a Java upgrade, what exact errors you might encounter, and how to fix them — in development, CI/CD, and production environments. […]

One of the most common errors Spring Boot developers face is: Web server failed to start. Port 8080 was already in use This error usually appears when your Spring Boot application starts successfully, but the embedded web server (Tomcat/Jetty/Undertow) cannot bind to port 8080. In this guide, you’ll learn: This explanation works for Windows, macOS,

Your application starts successfully, the startup logs look clean, and there are no exceptions. But when you try to access an API endpoint, nothing happens—or you receive a 404, 403, or no response at all. This issue occurs not only during local development but also in production deployments and CI/CD environments. In this guide, you’ll