How to fix the Julia language server in VS Code

Visual Studio is a powerful integrated development environment (IDE) developed by Microsoft, widely used for various types of software development. It supports a wide range of programming languages, including C#, C++, Python, JavaScript, TypeScript, and many others, making it versatile for different projects.

Using Julia in Visual Studio Code (VS Code) provides a robust environment for developing Julia applications.

Problem

VS Code may give the following error when using the Julia language server:

Could not start the Julia language server. Make sure the configuration setting julia.executablePath points to the Julia binary.

The above error means that the julia.exe can not start the language server, and it suggests checking if julia.executablePath points to the Julia binary.

Troubleshooting

Following are some steps you can take to troubleshoot this problem:

Install/Re-install: Make sure the Julia extension is installed in the VS Code. Re-installing also helps sometimes. For reference, you can review the documentation on the website of VS Code. https://code.visualstudio.com/docs/languages/julia
Compatibility issues: Make sure Julia and VS Code are updated. Try using the latest versions.

Check the path: Verify that the Julia executable is in the system’s path. You can also manually set the path to the Julia.exe in the VS Code. For this, go to “File"→"Preferences"→"Settings”. In the search bar, type julia.executablePath. Click the “Edit in settings.json” link. Now, add the julia.executablePath setting with the path to the Julia executable in the settings.json file. Modify according to the path where Julia is installed.

For Windows:
```
{
  "julia.executablePath": "C:\\Path\\To\\Julia\\bin\\julia.exe"
}
```
For Linux/MAC:
```
{
  "julia.executablePath": "/path/to/julia/bin/julia"
}
```

Update the language server: Open Julia in the terminal and switch to pkg mode with ] and update the LanguageServer package with the update LanguageServer command and restart VS code.
```
(@v1.4) pkg> update LanguageServer
```