Visual Studio Code – Why won't java recognize my .jar file, even though I put it in the referenced libraries of the project?

I have a .jar file I need in order to run my program, and VSCODE doesn’t recognize it as a package, when compiling my project.

I opened a settings.json file with these lines:
" { "java.project.referencedLibraries": [ "biuoop-1.4.jar" ] }"

And added the .jar file to the referenced libraries of the project. I expected it to work, since it stopped showing me errors. But it still doesn’t, and gives this message when compiling:

`AbstractArtDrawing.java:1: error: package biuoop does not exist
import biuoop.GUI;
             ^
AbstractArtDrawing.java:2: error: package biuoop does not exist
import biuoop.DrawSurface;
             ^
AbstractArtDrawing.java:8: error: cannot find symbol
    GUI gui = new GUI("AbstractArtDrawing", 400, 300);
    ^
  symbol:   class GUI
  location: class AbstractArtDrawing
AbstractArtDrawing.java:8: error: cannot find symbol
    GUI gui = new GUI("AbstractArtDrawing", 400, 300);
                  ^
  symbol:   class GUI
  location: class AbstractArtDrawing
AbstractArtDrawing.java:12: error: cannot find symbol
        DrawSurface d = gui.getDrawSurface();
        ^
  symbol:   class DrawSurface
  location: class AbstractArtDrawing
5 errors`