How to quit the program in Java SE??

Question

Hi,
The program below runs perfectly fine, however once I get to the stage of quitting it doesn't work.
I would like 'Press any key to continue' to appear once I have pressed q.
import java.util.Scanner;
public class Week7777
     public static void main(String[] args)
int j = 0;
                    while (j <1)
Scanner in = new Scanner(System.in);
          System.out.println("Enter the student's mark as a percentage ('q' to quit): ");
String input = in.nextLine();
int inputmark = Integer.parseInt(input);
char g = getGrade(inputmark);
if (inputmark<=100)
          System.out.println("The student's grade is " + g );
     else {
               System.exit();
j--;
     private static char getGrade(int mark)
               char grade= 0;
               if (mark >= 70)
               grade = 'A';
               else if (mark>= 60)
               grade ='B';
               else if (mark>= 50)
               grade ='C';
               else if (mark>= 40)
               grade ='D';
               else if (mark>= 30)
               grade ='F';
               return grade;
Please, can you help me sort out this problem.
Thank you

Answer 1

Hello Dr Clap
Thank you for your reply. I really appreciate it.
It's just that I have only recently started learning how to use Java, I am still building on my knowledge.
My program works, however once I get to quitting the program by pressing 'q', the following comes up, rather than 'Press any key to continue' which is the ideal.
"Exception in thread "main" java.lang.NumberFormatException: For input string: "q........"
I sent you the complete program, what details are you talking about?
I am not quite sure where I went wrong. So I would really appreciate it if you could help me.
Thank you
import java.util.Scanner;
public class Week77
public static void main(String[] args)
int j = 0;
while (j <1)
Scanner in = new Scanner(System.in);
System.out.println("Enter the student's mark as a percentage ('q'):");
String input = in.nextLine();
int inputmark = Integer.parseInt(input);
char g = getGrade(inputmark);
if (inputmark<=100)
System.out.println("The student's grade is " + g );
else
//else if the user does not enter the mark
                    System.exit(0);
j--;
private static char getGrade(int mark)
char grade= 0;
if (mark >= 70)
grade = 'A';
else if (mark>= 60)
grade ='B';
else if (mark>= 50)
grade ='C';
else if (mark>= 40)
grade ='D';
else if (mark<40)
grade ='F';
return grade;
}