Erro em while no Prompt [Resolvido]

import java.text.DecimalFormat;
import javax.swing.JOptionPane;


public class MediaTeste2 {


    public static void main ( String args [] )
    {
        int gradeCounter,
                gradeValue,
                total;
        double average;
        String input;

        total = 0;
        gradeCounter = 0;

        JOptionPane.showMessageDialog(null,
                "Valor maximo de nota é 100", " Informativo ", JOptionPane.INFORMATION_MESSAGE);

        input = JOptionPane.showInputDialog(null,
                "Coloque a nota\nPara finalizar digite -1", " Insira a Nota ", JOptionPane.PLAIN_MESSAGE);


        gradeValue = Integer.parseInt( input );
        
        if  ( gradeValue > 100 ) {
        JOptionPane.showMessageDialog(null,
                "Valor Invalido");
        return;
        }
        
         while ( gradeValue != -1 ) {

            total = total + gradeValue;

            gradeCounter = gradeCounter + 1;

            input = JOptionPane.showInputDialog(null,
                "Coloque a nota\nPara finalizar digite -1", " Insira a Nota", JOptionPane.PLAIN_MESSAGE);

            gradeValue = Integer.parseInt( input );
        }

        DecimalFormat twoDigits = new DecimalFormat( "0.00" );

        if ( gradeCounter != 0 ) {
            average = (double) total / gradeCounter;

            JOptionPane.showMessageDialog( null,
                  "Média da classe é " + twoDigits.format( average ),
                  "Média da Classe", JOptionPane.INFORMATION_MESSAGE );
        }
        else
            JOptionPane.showMessageDialog( null,
                    "Notas não digitadas", "Média da Classe",
                    JOptionPane.INFORMATION_MESSAGE );

        System.exit( 0 );

        }
    }

while ( gradeValue != -1 ) {^