New to Java

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.

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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;
}
}


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Please, can you help me sort out this problem.
Thank you