import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;

public class FileDemo
{

    public static void main(String[] args) throws IOException
    {
        File file = new File("D:/work/myfile.txt");

        /*
         * Returns the time that the file denoted by this
         * abstract pathname was last modified.
         * 
         * Returns: A long value representing the time the
         * file was last modified, measured in milliseconds
         * since the epoch (00:00:00 GMT, January 1, 1970),
         * or 0L if the file does not exist or if an I/O
         * error occurs
         */
        long lastModified = file.lastModified();
        System.out.println("Before Format : " + lastModified);

        SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
                                                "MM/dd/yyyy HH:mm:ss");

        String formatedStr = simpleDateFormat.format(lastModified);
        System.out.println("After Format : " + formatedStr);
    }

}