incompatible types error when providing a String to a method which requires a String

Question

i am trying to pass a String value into a method which accepts Strings, however i am getting the error "incompatible types". i have tried hard coding a int value to see what error it gives which i expected it to:

found int; required: java.lang.String.

changed the method to accept File instead which errors:

found String; required: java.io.File.

ergo, i am feeding a string where a string should be. but i don't understand where i am going wrong. (and i have changed it back to feed String and accept String)

any feedback is welcome. thanks in advance :)

import java.io.*;
import java.util.*;
public class Test
{
    private ArgsReader inputFile;
    private String filename;
    private List<Pallet> entryBayQueue;
    /**
     * Constructor for objects of class Test
     */
    public Test()
    {
        inputFile = new ArgsReader();
        entryBayQueue = new LinkedList();
    }

    /**
     * methods
     */
    public void run(String[] args)
    {
        if(args.length > 0) //launched if you gave an argument
        {
            String line;
            filename = args[0];
            System.out.println(filename.getClass().getSimpleName()); //outputs string


            line = inputFile.stringFileReader(filename); //call method containing reading capability to read and store contents in line

            // ******* here is where the error occurs

            //System.out.println(line); //line = null here
            StringTokenizer st = new StringTokenizer(line);//tokenize line's contents
            while(st.hasMoreTokens())
            {
                System.out.println(st.nextToken());
                int serialNum = 0;
                switch(st.nextToken())
                {
                    case "A": 
                        {
                            serialNum++;
                            Pallet almondPallet = new Pallet(1,serialNum); //create new almond pellet and assign serial number
                            entryBayQueue.add(almondPallet); //adds pallet to the end of the list
                            break;
                        }
                }
            }

        }
        else //launched when you didn't provide an argument
        {
            filename = null;
            Console console = System.console();
            filename = console.readLine("file to read from: ");
            inputFile.stringFileReader(filename); //call method containing reading capability
        }
    }
}

// ******this is the implementation of stringFileReader

public void stringFileReader(String filename)
    {
        try
        {            
            input = new FileReader(filename); //open file for reading (string filename)
            buffReader = new BufferedReader(input); // read a line at a time

            line = buffReader.readLine(); //read 1st line
            while (line != null)
            {
                lineNum++;
                System.out.println(line);
                line = buffReader.readLine(); //read next line
            }

        }
        catch (IOException e){System.out.println("caught IOException");}

Answer 1

public void stringFileReader(String filename)

was supposed to be

public String stringFileReader(String filename)

method was not returning values when call is expecting.

thanks anyone who was helping.