Java.util.inputmismatchException

Question

Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:840)
at java.util.Scanner.next(Scanner.java:1461)
at java.util.Scanner.nextInt(Scanner.java:2091)
at java.util.Scanner.nextInt(Scanner.java:2050)
at Trials.GradeBook.inputGrades(GradeBook.java:48)
at Trials.GradeBookTest.main(GradeBookTest.java:18)
could you plz xplain y i get this error message during building process

Answer 1

import java.util.Scanner;
public class GradeBook {
    private String courseName;
    private int total;
    private int gradeCounter;
    private int aGrade;
    private int bGrade;
    private int cGrade;
    private int dGrade;
    private int fGrade;
    // constructor of the class GradeBook
    public GradeBook(String name1) {
        courseName=name1;
    // initialize the value of the field courseName
    public void setCourseName(String name){
        courseName=name;
    // get the value of the field and return it to method caller
    public String getCourseName(){
        return courseName;
    // input the grades from user useing sentinel control loop
    public void inputGrades(){
        int grade;
        Scanner input = new Scanner(System.in);
        System.out.printf("%s\n%s\n%s\n",
                "Enter the integer grades between 0-100:",
                "Type end-of-file key to terminate the input",
                "(i.e <Ctrl>z then press Enter on Windows)");
        while(input.hasNext()){
            grade = input.nextInt();
            total += grade;
            ++gradeCounter;
            // call a method to increment appropriate grade counter
            incrementGradeCounter(grade);
    // mehtod incrementGradeCoutner counts using switch-case loop
    public void incrementGradeCounter(int grade){
        switch(grade/10){
            case 10:
            case 9:
                ++aGrade;
                break;
            case 8:
                ++bGrade;
                break;
            case 7:
                ++cGrade;
                break;
            case 6:
                ++dGrade;
                break;
            default:
                ++fGrade;
                break;
    // create a method that displays welcome message to grade book user
    public void displayMessage(){
        System.out.printf("\nWelcome to the Grade Book for %s\n",
                getCourseName());
    public void displayReport(){
        if ( gradeCounter != 0 ){
            System.out.printf("The total of %d grade entered is %d\n",
                    gradeCounter,total);
            System.out.printf("The class average is %.2f",
                    (double)total/gradeCounter);
            System.out.printf("%s\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n",
                    "Number of students who recieved each grade",
                    "A: ",aGrade,
                    "B: ",bGrade,
                    "C: ",cGrade,
                    "D: ",dGrade,
                    "F: ",fGrade);
        else
            System.out.println("Sorry! no grade was entered\n" +
                    "THANK YOU FOR USING THE GRADE BOOK");
public static void main(String args[]) {
        // create an object of Class GradeBook with its own contructor
        GradeBook myGradeBook = new GradeBook("CS101 Java Programming");
        myGradeBook.displayMessage();
        myGradeBook.inputGrades();
        myGradeBook.displayReport();
    }}