VS Code Java SDK Creates Project Errors on Default Components (Main Method, Double, String etc.)

Question

Environment: I had a series of unexplainable errors on a macOS system running macOS Big Sur and while I was trying to run my application using this guide from the official VS Code website.

Issue: Every time I opened a certainly working project in VS Code (tested in the IntelliJ IDE), it was full of errors like String is not a known class or main method not defined in class etc.

Understanding the Problem: I quickly figured out that the issue has to do with the JDK being misconfigured, and now I had to figure out if the issue was in VS Code or Homebrew. The issue I suspected lied in VS Code and originated from my choice to use a JDK downloaded and managed by the Homebrew package manager. After verifying my Homebrew installation of the given cask and making sure system paths were set correctly, I was certain of the previously made assumption.

Answer 1

Solution:

1. Open the folder in VS Code
2. Collapse the Java Projects Tab in the Explorer menu (make sure you have the [java language package extension][3] downloaded)
3. Click the three dots icon '...' which appears when you hover over the Java Projects area with your mouse.
4. Select 'Configure Java Runtime'. A new tab will open.
5. On the Java Version column, select the pencil icon.
6. Open the dropdown menu and select a Java Version from the Java Virtual Machines folder instead of opt/Homebrew directories (it may be the same JDK from Homebrew using an alias, but VS Code expects the Virtual Machine folder and that is my theory in why this works).