Your company’s modern build tool of choice (Maven or Gradle). We lean on this for both dependency management as well as building our deployable application artifacts.
Distributed source control with Git. You should be comfortable with the basic commands on the command line, including clone, fetch/merge/pull, add/rm, commit, and push.
Your IDE of choice. For example, Eclipse with the Spring Tools Suite or JetBrains IntelliJ IDEA. While we want our application and its build process to be decoupled from its development environment, you are going to use it every day during your project. It pays to get familiar with common actions. You should be comfortable with the basics of creating and importing new projects, standard code navigation, and generic refactoring commands. You should also be familiar with how to run tests within your favorite IDE, as you will do that a lot.
Review the applicable tutorial(s) from Java 8 through your current version of Java.