read multiple text files from particular folder and want to get name of the file inside each file and changes made should be shown on the excisting file itself

import java.io.*;
import java.io.FileReader;

public class rrr
{
    public static void main(String args[])throws IOException
    {
        String p="E:\\folderA";
       
   File dir=new File(p);
      File[]  files=dir.listFiles();
            for(File f : files)
              if(f.isFile())
                

           { 

              BufferedReader  ins=null;
             ins=new BufferedReader(new FileReader(f));
               String line;
             
             
                    
             System.out.print("[");
             System.out.print(f.getName());
             System.out.print("_DINAMALAR_DATE]\n");
            
    
           

                {
   while((line=ins.readLine())!=null)
                     {
                              System.out.println(line);
                     }
            
              
          }
     
           }}}