Creating two files and check if they are equal. The two files are different charset and line separator.

TestFile.java

package com.test;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Writer;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class TestFile {
    public static void main(String... args){
        new TestFile().createFiles();
        new TestFile().readFiles();
        new TestFile().readFiles2();
    }

    private void readFiles2() {
        List<List<String>> lines = Stream.of("sjis", "utf8").map(charset -> {
            Path path = Paths.get("/Users/tomo/file" + charset + ".txt");
            try {
                return Files.readAllLines(path, Charset.forName(charset));
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }).collect(Collectors.toList());
        if (lines.get(0).equals(lines.get(1))) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
    }

    private void readFiles() {
        List<String> sjisLines = readFile("sjis");
        List<String> utfLines = readFile("utf8");
        System.out.println(sjisLines);
        System.out.println(utfLines);
        if (sjisLines.equals(utfLines)) {
            System.out.println("OK");
        } else {
            System.out.println("NG");

        }
    }

    private List<String> readFile(String charset) {
        Path path = Paths.get("/Users/tomo/file" + charset + ".txt");
        List<String> lines = new ArrayList<>();
        try (BufferedReader reader = Files.newBufferedReader(path, Charset.forName(charset))) {
            String line = null;
            while ((line = reader.readLine()) != null) {
                lines.add(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return lines;
    }

    private void createFiles() {
        String crlf = "\r\n";
        String lf = System.getProperty("line.separator");
        List<String> contents = Arrays.asList("１行め", "２行め");
        createFile(contents, crlf, "sjis");
        createFile(contents, lf, "utf8");
    }

    private void createFile(List<String> contents, String linesep, String charset) {
        Path path = Paths.get("/Users/tomo/file" + charset + ".txt");
        try (Writer writer = Files.newBufferedWriter(path, Charset.forName(charset), StandardOpenOption.CREATE,
                StandardOpenOption.TRUNCATE_EXISTING)) {
            String lines = contents.stream().collect(Collectors.joining(linesep));
            writer.write(lines);
        } catch (IOException e){
            e.printStackTrace();
        }

    }
}