General tips:

  • Press F1 when your cursor is on a method or variable to see its java documentation.
  • To run a class, right click on it in the file view and choose Run main(). If it doesn’t have that option, be sure your class has a public static void main(String args[]) function and that you made args be an array!
    • Or you can click the green “play button” that will appear next to your main() function in the editor.
  • You can use IntelliJ to commit and push your code to GitHub.
    • From the VCS menu choose Commit and be sure your modified files are all selected.
    • Inside the commit window, type your message and type your name in the top right
    • Uncheck all boxes under Before Commit
    • Be sure to click the little arrow next to Commit and select Commit and Push
      • Otherwise your code will not be uploaded!
      • Your screen should look like:


Reducing the amount of pointless suggestions IntelliJ gives. This will eliminate many of the light bulb icons that IntelliJ adds for minor language features that we don’t particularly care about.

  • Open the Settings (Windows) or Preferences (Mac) window in IntelliJ.
  • Expand Editor and click Inspections
  • At the top of window change the Profile to “Stored in IDE - Default”
  • Click on Java and then on the right side of the window change the Severity to Typo

Importing a project from github.

  • Click the VCS menu and choose Checkout from Version Control... and pick Git. OR from the Welcome screen click Checkout from Version Control...
    • IMPORTANT: DO NOT TRY TO CHECK OUT A PROJECT BY SELECTING New -> Project from Verson Control. This will not work correctly!
  • You do not need to click Login to GitHub, just enter the git URL you want to clone.
  • Click Yes when IntelliJ asks you about creating a new project. Continue to click Next/Yes until the project opens.

No SDK Warning:

  • If you get a message at the top of the screen saying there is no SDK selected, then you will not be able to compile or run any java programs.
  • To solve this, click the button to configure an SDK.
  • Hit the plus button or hit “New…” and select JDK
  • This should give a file browser. Go to where the Java JDK is installed (see below), which is most likely something like C:\Program Files\Java\jdk1.8 on Windows.

No Output Directory Error:

  • This usually happens when you did not follow the instructions above for importing a github repo into a new project - so try to follow that again carefully! (i.e., NEVER use File->New)
  • If you still have the problem, then in the Project Structure menu there is a place to specify an output directory. Use that to create a new folder named out inside your project and select that. This is where IntelliJ will place your compiled files.