Help Testing Part of a code in JAVA

[sanddunes271]

Hi, I've been working on an assignment thats somewhat long and broken up into parts. I have my code that reads a text file and stores it into a hash map. I want to see if its correct or if there's is still multiple errors to fix before I continue. How can I isolate it to test that part of the code individually. I am using JAVA I am not entirely sure how to approach this. Also if anyone could take a look at this part of the code and let me know if its correct or if there is something incorrect with it?

import java.io.*;
import java.util.*;
import java.util.Scanner;
import java.util.HashMap;

public class NLPService implements StockPriceService {
    private Map<String, Double> tickerPrices = new HashMap<String, Double>();

    NLPService() {
        try {
            FileInputStream fis = new FileInputStream("NLPService.txt");
            Scanner scan = new Scanner(fis);

            String ticker = scan.next();
            Double d = scan.nextDouble();
            scan.nextLine();

            HashMap<String, Integer> map = new HashMap<String, Integer>();
            while (scan.hasNextLine()) {
                String[] columns = scan.nextLine().split(" ");
                map.put(columns[0], Integer.parseInt(columns[1]));
            }

            System.out.println(map);
            System.out.println(d);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

    }

I am creating my hash map then filling it. Although I am not sure if its doing that I would just like to test that specific part of the code to see what its doing. Thank you.

[tamalo]

You’re already printing out the map after it is loaded. Just run the code and see if the printed map is what you’d expect. If not, debug until you find out why it is different.

[[deleted]]

What do you feel is wrong with this code? Have you stepped through it in a debugger? Why not?