Java - Asignar nombre de PDF a copia en TXT

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.BufferedWriter;

import java.io.IOException;

import com.itextpdf.text.Document;

import com.itextpdf.text.pdf.PdfReader;

import com.itextpdf.text.pdf.parser.PdfTextExtractor;

import java.awt.Desktop;

import javax.swing.filechooser.FileNameExtensionFilter;

import javax.swing.JFileChooser;

public class PDFToTextConverter{

 public static void main(String[] args){

  selectPDFFiles();

 }

 //allow pdf files selection for converting

 public static void selectPDFFiles(){

  JFileChooser chooser = new JFileChooser();

      FileNameExtensionFilter filter = new FileNameExtensionFilter("PDF","pdf");

      chooser.setFileFilter(filter);

      chooser.setMultiSelectionEnabled(true);

      int returnVal = chooser.showOpenDialog(null);

      if(returnVal == JFileChooser.APPROVE_OPTION) {

               File[] Files=chooser.getSelectedFiles();

               System.out.println("Please wait...");

               for( int i=0;i<Files.length;i++){

                convertPDFToText(Files[i].toString(),"textfrompdf"+i+".txt");

                }

   System.out.println("Conversion complete");

                }

  }

 public static void convertPDFToText(String src,String desc){

  try{

   //create file writer

   FileWriter fw=new FileWriter(desc);

   //create buffered writer

   BufferedWriter bw=new BufferedWriter(fw);

   //create pdf reader

   PdfReader pr=new PdfReader(src);

   //get the number of pages in the document

   int pNum=pr.getNumberOfPages();

   //extract text from each page and write it to the output text file

   for(int page=1;page<=pNum;page++){

    String text=PdfTextExtractor.getTextFromPage(pr, page);

    bw.write(text);

    bw.newLine();

   }

   bw.flush();

   bw.close();

  }catch(Exception e){e.printStackTrace();}

 }

}

for( int i=0;i<Files.length;i++){

    String nameFile=Files[i].getName();//te retorna el nombre con la extension del archivo ejemplo: mi_archivo.pdf

    //quitamos la extensión

     String nombreTxt=nameFile.substring(0,nombre.lastIndexO f("."))+".txt";//agregamos la extensión txt

    convertPDFToText(Files[i].toString(),nombreTxt);//llamamos a tu metodo.

}