I just started working on a personal project in Java. I didn't learn about reading and writing to files in the class I took but I'm reading a book online about it. I'm pretty sure I'm doing it right, but it keeps throwing an error at me.

Code:
import java.io.*;
import java.util.*;
/**
 * Controls the saving, loading, and handling of arrays with information.
 * 
 * @author Nicholas Leveillee
 * @version May 11, 2010
 */
public class GameFunctions
{
    
    /**
     * Constructor for objects of class GameFunctions
     */
    public GameFunctions()
    {
        
    }
    
    //This method prompts for the current Operating System
    public void learnOS()
    {
        int ans = 0;
        Scanner input = new Scanner(System.in);
        if(ans>3 || ans <1){
            System.out.println("What is your operating System? (1) Windows (2) Macintosh (3) UNIX/Linux variants");
            System.out.print("Enter the number: ");
            ans = input.nextInt();
        }
        System.out.println("Thank you!");
        //The next if block changes the numeric answer to a string
        String oS = null;
        if(ans == 1){
            oS = "Win";
        }
        else if(ans == 2){
            oS = "Mac";
        }
        else if(ans == 3){
            oS = "Lin";
        }
        //Need to write to a text file, in the same directory.
        PrintWriter sys;
        try{
            sys = new PrintWriter(new FileWriter("system.txt"));
        }
        catch (IOException e){ //Exit if there is an error
            System.out.println("Error: " + e);
            return;
        }
        try{
            sys.print(oS);
        }
        finally{
            sys.close();
        }
    }
    
    //This method returns the operating system, for use in other classes
    public String getOS()
    {
        String oS = null;
        //Setup a file reader and read the first line of system.txt
        TextReader sys; //ERROR HERE:cannot find symbol - class Text Reader
        try {
            sys = new TextReader(new FileReader("system.txt"));
        }
        catch(FileNotFoundException e){
            return;
        }
        try{
            oS = sys.getln;
        }
        catch(IOException e){
            System.out.println("Error: " + e.getMessage());
        }
        finally{
            sys.close();
        }
        return oS;
    }
}