Renamer

import java.io.*;
import java.util.Date;
import java.text.SimpleDateFormat;

public class Renamer {

    public static void main(String[] args) {

        String filesDir = "C:\\OriginalFiles";
        String convertedDir = "C:\\RenamedFiles";

        String[] files = new java.io.File(filesDir).list();
        File oldFile[] = new File(filesDir).listFiles(), dest = new File(convertedDir);

        for( int i = 0; i < files.length; i++ ) {
            Date todaysDate = new java.util.Date();
            SimpleDateFormat formatter = new SimpleDateFormat("dd_MM_yyyy_HH_mm_ss");
            String formattedDate = formatter.format(todaysDate);
            int extdotpos = files[i].lastIndexOf(".");
            String newName = formattedDate + files[i].substring(extdotpos);
            oldFile[i].renameTo(new File(dest, newName));

            System.out.println(files[i] + " > " + newName);

            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) { }
        }
    }
}