Answer 1: You can create an executable JAR file by using the following Maven command mvn clean install.
Answer 2: The easiest way to deploy Spring Boot application is to push your application source code to the GitHub and use GitHub link from the Heroku.
Answer 3: The easiest way to deploy the React app to Heroku is to use the Heroku Buildpack for create-react-app (https://github.com/mars/create-react-app-buildpack).
Answer 4: Docker is a container platform that makes software development, deployment, and shipping easier. Containers are lightweight and executable software packages that include everything that is needed to run software.
Answer 5: The Spring Boot application is just an executable JAR file that can be executed with Java. Therefore, you can create Docker container for Spring Boot application similar way than you create for any Java JAR application...
