Convertir un archivo de texto en mayúsculas Ejercicio Java - Curso de Programación Java

package FileLowerCaseToUpperCase;
import java.util.*;

public class Main
{
	public static void main(String[] args)
	{
		System.out.print("Enter name file: ");
		String fileName = new Scanner(System.in).nextLine();

		if ((new java.io.File(fileName)).isFile())
		{
			java.io.FileReader fileRw = new java.io.FileReader(fileName);
		java.io.BufferedReader fileRwBufferedReader = new java.io.BufferedReader(fileRw);
			java.io.FileWriter fileWr = new java.io.FileWriter(fileName + ".dat");
			String line;
			do
			{
				line = fileRwBufferedReader.readLine();
				if (line != null)
				{
					fileWr.write(line.toUpperCase() + System.lineSeparator());
				}
			} while (line != null);
			fileRw.close();
			fileWr.close();
		}
	}
}