Поток чтения, методология.

import java.io.*;


/*
C:\Users\yunus\Desktop\index.html
*/

public class Solution {
    public static void main(String[] args) {
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));) {
            String fileName = reader.readLine();

            try (BufferedReader readerFile = new BufferedReader(new FileReader(fileName))) {
                while (readerFile.ready()) {
                    String line = readerFile.readLine();
                    System.out.println(line);
                }
            }

        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}