Development tools

Install a JDK 21, Apache Maven 3.9+, and an IDE such as IntelliJ IDEA, Eclipse/STS, or VS Code with Java extensions. Maven must be on PATH and JAVA_HOME must point to the JDK directory, not its bin subdirectory. Use a terminal in the project folder. Internet access is needed on the first dependency download. Spring Boot projects include an embedded Tomcat server. The Servlets and JSPs tutorial explains how to install Tomcat separately.

For the React lab, also install Node.js 22.12+ and npm. For the REST labs, install Postman Desktop, or use the web client with its Desktop Agent for localhost requests.

java -version
javac -version
mvn -version
node --version
npm --version

Expect Java and javac to report version 21, Maven to report 3.9.x and its Java home, and Node to report a supported 22.x or newer version. If multiple JDKs are installed, Maven’s reported Java version determines compilation. The projects target Java 21; using an older JDK causes “release version 21 not supported.”

These examples deliberately pin Boot 4.1.1. Boot 4’s MVC starter is spring-boot-starter-webmvc; its MongoDB connection property is spring.mongodb.uri. When reading a Boot 3 tutorial, check its starter and configuration names before mixing it with this code.

Version references: Spring Boot requirements, Boot configuration properties, and Vite setup.