Java code to list all files in a directory and sub-directories

//Java code to list all files in a directory and sub-directories

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.attribute.BasicFileAttributes;

import com.csvreader.CsvWriter;

public class FilesFromDirectories {
 
    static long fileSize;
     static String size;
       
     static CsvWriter csvOutput;
     
    public static <lang> void main(String a[]) throws IOException{
     
//Folder path
    File file = new File(" D://learn");
        

//Out put csv file
    File file2 = new File("D:\\output.csv");

    if ( !file2.exists() ){
        file2.createNewFile();
    }
    csvOutput= new CsvWriter(new FileWriter(file2, true), ',');
        
        csvOutput.write("File Name");
        csvOutput.write("Creation Time");
        csvOutput.write("Size");
        csvOutput.write("Full Path");
        csvOutput.endRecord();
        listfiles(file.toString());
        
    }


public static void listfiles(String directoryName) throws IOException {
        File directory = new File(directoryName);
         BasicFileAttributes attributes = null;
        File[] fList = directory.listfilesiles();
        try
        {
        for (File f : fList) {
            if (f.isFile()) {
            attributes = Files.readAttributes(f.toPath(), BasicFileAttributes.class);
                //System.out.println("File Name ="+f.getName());
                fileSize= f.length(); 
                size=String.valueOf(fileSize);
                //System.out.println("File Size :: " + fileSize);
               // System.out.println("File Size :: " + f);
                System.out.println("File Name  :: "+ f.getName()+"Size :: "+ size + "Full Path "+f.toString());
                System.out.println("Creation Time ::"+attributes.creationTime());
        csvOutput.write(f.getName());
csvOutput.write(attributes.creationTime().toString());
        csvOutput.write(size);
    csvOutput.write(f.toString());
   
      csvOutput.endRecord();
      
              } else if (f.isDirectory()) {
                System.out.println(f);
            listfiles(f.getAbsolutePath());
            }
          
     csvOutput.flush();
        }
        }
        catch(IOException exception)
        {
        System.out.println("Exception handled when trying to get file " +
                     "attributes: " + exception.getMessage());
        }
    }
    
}