Compare Csv file


ok, i got it something, works but not so pretty :slight_smile:

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVPrinter;
import org.apache.commons.csv.CSVRecord;

import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;

String originalPath = System.getProperty("user.dir")+"\\ExcelFiles\\original.csv";
String comparePath = System.getProperty("user.dir")+"\\ExcelFiles\\compare.csv";
String differencesPath = System.getProperty("user.dir")+"\\ExcelFiles\\differences.csv";

int[] rowsCols = getRowsColsNo(originalPath);
int[] rowsCols2 = getRowsColsNo(comparePath);
System.out.println(rowsCols[0]); //count of rows
System.out.println(rowsCols[1]); //count of columns

File file = new File(differencesPath);
	System.out.println("File deleted successfully");
	System.out.println("Failed to delete the file");
createCSVFile(differencesPath);//create new file

String mess = "original.csv does not match with compare.csv ";
//start from row 0 (header)
writeToDiffFile(differencesPath, null, mess, 0, 0);//write header wrote
String[] strDiff = new String[rowsCols[0]];
for (int i = 0; i < rowsCols[0]; i++) {
	String line = Files.readAllLines(Paths.get(originalPath)).get(i);
	String line2 = Files.readAllLines(Paths.get(comparePath)).get(i);
	String diff = getDiff(line, line2);
	strDiff[0] = diff;
	strDiff[1] = "in row "+i;
	writeToDiffFile(differencesPath, strDiff, null, 1, i);

public static int[] getRowsColsNo(String fileName) {
	Scanner scanIn = null;
	int rows = 0;
	int cols = 0;
	String InputLine = "";
	try {
		scanIn = new Scanner(new BufferedReader(
				new FileReader(fileName)));
		while (scanIn.hasNextLine()) {
			InputLine = scanIn.nextLine();
			String[] InArray = InputLine.split(",");
			cols = InArray.length;

	} catch (Exception e) {
	return [rows, cols] ;

public static void createCSVFile(String fileName) throws IOException {
	//String[] HEADERS = { "author", "title","year"};
	CSVPrinter printer = null;
	FileWriter out = new FileWriter(fileName);
	try {
		printer = new CSVPrinter(out, CSVFormat.DEFAULT);
		//        .withHeader(HEADERS));
	} catch (IOException e) {

public static void writeToDiffFile(String fileName, String[] values, String val, int counter, int rowNum) throws IOException {
	CSVPrinter csvPrinter;
	//FileWriter out = new FileWriter(fileName);
	Writer writer = Files.newBufferedWriter(Paths.get(fileName), StandardOpenOption.APPEND);
	//BufferedWriter writer = Files.newBufferedWriter(Paths.get(fileName), StandardOpenOption.APPEND);
	if(counter == 1) {
		csvPrinter = new CSVPrinter(writer, CSVFormat.DEFAULT);
		 //       .withHeader("author", "title", "year"));
		csvPrinter = new CSVPrinter(writer, CSVFormat.DEFAULT);

public static String getDiff(String str1, String str2){
	String[] strList1 = str1.split(",");
	String[] strList2 = str2.split(",");

	List<String> list1 = Arrays.asList(strList1);
	List<String> list2 = Arrays.asList(strList2);

	// Prepare a union
	List<String> union = new ArrayList<>(list1);

	// Prepare an intersection
	List<String> intersection = new ArrayList<>(list1);

	// Subtract the intersection from the union
	List<String> arr = new ArrayList<>();
	for (String s : union) {
	return String.join(", ", arr);

“Dan Simmons”,“Hyperion”,2019
“Douglas Adams”,“The Hitchhiker’s Guide to the Galaxy”,2020
“Mat Pat”,“Java Book”,2018
“Tim Given”,“Maths”,2015

“Dan Simmons”,“Hyperion”,
,“The Hitchhiker’s Guide to the Galaxy”,2020
“Mat Pat”,“Java Book”,100
“Tim Given”,


“original.csv does not match with compare.csv "
“”,in row 0,
2019,in row 1,
“”“Douglas Adams””, “,in row 2,
“2018, 100”,in row 3,
“”“Maths””, 2015",in row 4,

Hi @Timo_Kuisma1,
I’m trying to use this code for comparing CSV files and writing the differences, But when I ran the test case it’s getting fail could you please help to figure out the issue of this.


do you have import these classes

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVPrinter;
import org.apache.commons.csv.CSVRecord;

if not
then download .jar from

and add it to the Drivers folder

@kazurayam, Is it possible to launch WinMerge from Katalo studio? I need to do exactly this for my testing needs. Appreciate your help.


which files you should merge with WinMerge, maybe you can use java code to merge files

Following post shows how to execute an exe from Katalon Test Case. The following case takes “ipconfig” command, but essentially the same method applies for WinMerge CLI.

The WinMerge doc tells how to execute it in commandline

hi @Timo_Kuisma1,
Thanks for your response, I tried as you suggested but still no luck getting the same error.
Below are the attachments could you pls verify and correct me.


You put the jar into the KatalonInstallationFolder\configuration\resources\drivers folder. That is not the appropriate place.

You should put the jar into the <yourProjectFolder>\Drivers folder. And you should stop/restart Katalon Studio to let it acknowledge the new jar in the Drivers folder.

Thank You @kazurayam i will change the path and i will try.

hi @kazurayam i changed the path even through getting the same error.


do as Kazu said, restart Katalon studio to get .jar files into the classpath

Could you take a screenshot of the <yourProjectDir>\Drivers folder and share it?

hi @kazurayam below is the screenshot of project drivers folder.

This looks strange.

Could you take a screenshot of the <yourProjectDir>?

sure,this is my project directory

In Katalon Studio, open your project and in the tool bar call Project > Settings

then select the menu External Libraries:

Do you find commons-csv-1.8.jar there?

It seems you have put a folder named commons-csv-1.8. That is not the way you should do.

The contents of the folder would look like this:

You should pick up a jar file named commons-csv-1.8.jar only, and drop it into the <yourProjectDir>\Drivers folder.

nothing is there in my external libraries

could you pls share me the link of jar files.

Maven Central provides an immediate link to the jar:

Yes, Now I added and in my project external libraries also it’s showing I ran the program still getting these error even I imported those two.