https://learn-spring-boot-4.pages.dev/01-introduction/index.htmlGet a JDK and a generated project running, then meet the parts every Spring Boot app is made of.Hugoenhttps://learn-spring-boot-4.pages.dev/01-introduction/00-setup/index.htmlMon, 01 Jan 0001 00:00:00 +0000https://learn-spring-boot-4.pages.dev/01-introduction/00-setup/index.htmlInstall the JDK Spring Boot 4 needs Java 17 or newer and supports Java 25. Take the newest LTS: # macOS brew install --cask temurin@25 # Linux sudo apt install openjdk-25-jdk # Windows winget install EclipseAdoptium.Temurin.25.JDK # any platform, several versions side by side sdk install java 25-tem # sdkman.io java --version # openjdk 25 … No Maven or Gradle install needed — generated projects ship a wrapper.https://learn-spring-boot-4.pages.dev/01-introduction/01-first-app/index.htmlMon, 01 Jan 0001 00:00:00 +0000https://learn-spring-boot-4.pages.dev/01-introduction/01-first-app/index.htmlThe entry point package com.example.demo; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); } } @SpringBootApplication is three annotations in one: Annotation Job @SpringBootConfiguration this class may declare beans @ComponentScan find components in this package and below @EnableAutoConfiguration configure what the classpath suggests Warning Component scanning starts at the application class’s package. Keep it at the root — classes in a sibling package are invisible.