When updating to Java 11 from an older version of the language, make sure that your development environment is up to date. Otherwise you will receive the “Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project: Fatal error compiling: invalid target release: 11” error while building a project with Maven. Follow the checklist in this post to adjust the required settings for building a Spring Boot application.
Developing a multi-module application where the backend runs on Spring Boot and the frontend is powered by Angular is far less complicated than one might expect. Check out how you can build such a project and manage it as a single jar file.