Help with text based options

I am currently working on a program that will input a .txt file, read the numbers from there and calculate different things about it. I am struggling where the user inputs the data. I keep getting the error- Cannot find symbol - method exists(). I am trying to have the user enter in a file name, then the program checks if it is a file, if not it should go into a loop saying "invalid file" and re-prompts the user to enter their file name again. My code is pasted below, any suggestions?



import java.util.Scanner;
import java.io.File;
import java.io.IOException;
import java.io.*;

public class Grades
{
public static void main ( String [] args ) throws IOException
{
int grade;
int kids = 0;
int max = 0;
int min = 100;
int passing = 0;
int a = 0;
int b = 0;
int c = 0;
int d = 0;
int f = 0;
int sum = 0;
int number;

String input2 = new String("input2");
Scanner input = new Scanner ( System.in );

System.out.println( "\n This program is designed to open a .txt file containing grades and display several statistics about the grades.");
System.out.println(" " );
System.out.println( "The availible input files, where you may input grades are:"
+ "\n\t Grades.txt"
+ "\n\t Grades2.txt"
+ "\n\t Grades3.txt"
+ "\n\t Grades4.txt"
+ "\n\t Grades5.txt");
System.out.print( "Please enter the filename that contains the grades you wish to use from the list above: ");
String file = input.nextLine();

File inputFile = new File(file);

while ( file.exists() == false )
{
System.out.println("\n File not found");
System.out.print("Please re-enter filename: ");
String file = input.nextLine();
}

Scanner con = new Scanner( inputFile );