Programming Tutorials

The Crash You have just bumped your version numbers in  pom.xml  or  build.gradle  to upgrade from Spring Boot 2.7 to Spring Boot 3.0+. You compile successfully, but upon runtime startup or the first HTTP request, the application crashes with a stack trace resembling this: java.lang.NoClassDefFoundError: javax/servlet/http/HttpServletRequest at com.example.config.SecurityConfig.configure(SecurityConfig.java:24) at ... Caused by: java.lang.ClassNotFoundException: javax.servlet.http.HttpServletRequest at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) ... Or perhaps an error related to JPA: java.lang.NoClassDefFoundError: javax/persistence/Entity This is the single most common blocking issue in Spring Boot 3 migrations. It is not a bug in your code logic; it is a binary incompatibility caused by a massive ecosystem sh...