Could not find or load main class error when using makefile

Question

I've got a makefile that looks like this. Program with same exact project structure works just fine on intellij and the unix system I'm using yet for some reason this particular main in GameScreen isn't working. Any advice would be appreciated

default:cpsc2150/Project3/AbsGameBoard.java cpsc2150/Project3/BoardPosition.jav\
a cpsc2150/Project3/GameBoard.java cpsc2150/Project3/GameScreen.java cpsc2150/P\
roject3/IGameBoard.java cpsc2150/Project3/GameBoardMem.java

        javac cpsc2150/Project3/AbsGameBoard.java cpsc2150/Project3/BoardPositi\
on.java cpsc2150/Project3/GameBoard.java cpsc2150/Project3/GameScreen.java cpsc\
2150/Project3/IGameBoard.java cpsc2150/Project3/GameBoardMem.java

run: cpsc2150/Project3/AbsGameBoard.class cpsc2150/Project3/BoardPosition.class\
 cpsc2150/Project3/GameBoard.class cpsc2150/Project3/GameScreen.class cpsc2150/\
Project3/IGameBoard.class cpsc2150/Project3/GameBoardMem.class

        java cpsc2150/Project3/GameScreen
clean:
        rm cpsc2150/Project3/*.class

Heres the start of my GameScreen file as well

import java.util.*;
public class GameScreen {
    public GameScreen(){

    }
    //@invariant- xCoord >=0, xCoord <=8, yCoord >=0, yCoord <=0
    //rndNum >=0
    public static void main(String [] args) {