How can I get this to run another time?

Question

public static void main(String[] args) {
    
    Scanner s = new Scanner(System.in);
    
    
    final int STUDENT_SIZE = 50;
    
    
    
    int i = 0;
    char choice1 = 'y';
    
    String [] stdntName = new String [50];
    String [] WIDNUM = new String [STUDENT_SIZE];
    int [] EXM1 = new int [STUDENT_SIZE];
    int [] EXM2 = new int [STUDENT_SIZE];
    int [] EXM3 = new int [STUDENT_SIZE];
    int [] finalExm = new int [STUDENT_SIZE];
    
    
    for (i=0; i < stdntName.length; i++) {
        
        System.out.print("Please enter the name of Student " + (i+1) + ": ");
        stdntName[i] = s.nextLine();   
        
        System.out.println("Please enter the WID of Student " + (i+1) + ": ");
        WIDNUM[i] = s.nextLine();
        
            if (WIDNUM[i].length() != 9 ) {
                System.out.println("**Invalid WID...must be 9-digits");
                System.out.println("Please re-enter score:");
                WIDNUM[i] = s.nextLine();
            }
            
        System.out.println("Please enter score for Exam 1: ");
        EXM1[i] = s.nextInt();
        
            if (EXM1[i] < 0 || EXM1[i] > 50) {
                System.out.println("**Invalid score...please enter 0-50 only");
                System.out.println("Please re-enter score: ");
                EXM1[i] = s.nextInt();
            }
        
        System.out.println("Please enter score for Exam 2 ");
        EXM2[i] = s.nextInt();
        
            if (EXM2[i] < 0 || EXM2[i] > 50) {
                System.out.println("**Invalid score...please enter 0-50 only");
                System.out.println("Please re-enter score: ");
                EXM2[i] = s.nextInt();
            }
        
        System.out.println("Please enter score for Exam 3 ");
        EXM3[i] = s.nextInt();
        
            if (EXM3[i] < 0 || EXM3[i] > 50) {
                System.out.println("**Invalid score...please enter 0-50 only");
                System.out.println("Please re-enter score: ");
                EXM3[i] = s.nextInt();
            }
        
        System.out.println("Please enter score for Final Exam ");
        finalExm[i] = s.nextInt();
        
            if (finalExm[i] < 0 || finalExm[i] > 100) {
                System.out.println("**Invalid score...please enter 0-100 only");
                System.out.println("Please re-enter score: ");
                finalExm[i] = s.nextInt();
            }

            System.out.print("Do you wish to enter another? (y/n): ");
            choice1 = s.nextLine().toLowerCase().charAt(0); // read entire line
            if (choice1 != 'y') {
                break;
            }
                  
  }
 }  
}

This is the error message:

Do you wish to enter another? (y/n): Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 0 at java.base/java.lang.StringLatin1.charAt(StringLatin1.java:48) at java.base/java.lang.String.charAt(String.java:712) at Proj4.main(Proj4.java:77)

Answer 1

Just add s.nextLine() because you scanner was not reaching the point to get your choice1

Your code fixed

 public static void main(String[] args) {

            Scanner s = new Scanner(System.in);


            final int STUDENT_SIZE = 50;



            int i = 0;
            char choice1 = 'y';

            String [] stdntName = new String [50];
            String [] WIDNUM = new String [STUDENT_SIZE];
            int [] EXM1 = new int [STUDENT_SIZE];
            int [] EXM2 = new int [STUDENT_SIZE];
            int [] EXM3 = new int [STUDENT_SIZE];
            int [] finalExm = new int [STUDENT_SIZE];


            for (i=0; i < stdntName.length; i++) {

                System.out.print("Please enter the name of Student " + (i+1) + ": ");
                stdntName[i] = s.nextLine();

                System.out.println("Please enter the WID of Student " + (i+1) + ": ");
                WIDNUM[i] = s.nextLine();

                if (WIDNUM[i].length() != 9 ) {
                    System.out.println("**Invalid WID...must be 9-digits");
                    System.out.println("Please re-enter score:");
                    WIDNUM[i] = s.nextLine();
                }

                System.out.println("Please enter score for Exam 1: ");
                EXM1[i] = s.nextInt();

                if (EXM1[i] < 0 || EXM1[i] > 50) {
                    System.out.println("**Invalid score...please enter 0-50 only");
                    System.out.println("Please re-enter score: ");
                    EXM1[i] = s.nextInt();
                }

                System.out.println("Please enter score for Exam 2 ");
                EXM2[i] = s.nextInt();

                if (EXM2[i] < 0 || EXM2[i] > 50) {
                    System.out.println("**Invalid score...please enter 0-50 only");
                    System.out.println("Please re-enter score: ");
                    EXM2[i] = s.nextInt();
                }

                System.out.println("Please enter score for Exam 3 ");
                EXM3[i] = s.nextInt();

                if (EXM3[i] < 0 || EXM3[i] > 50) {
                    System.out.println("**Invalid score...please enter 0-50 only");
                    System.out.println("Please re-enter score: ");
                    EXM3[i] = s.nextInt();
                }

                System.out.println("Please enter score for Final Exam ");
                finalExm[i] = s.nextInt();

                if (finalExm[i] < 0 || finalExm[i] > 100) {
                    System.out.println("**Invalid score...please enter 0-100 only");
                    System.out.println("Please re-enter score: ");
                    finalExm[i] = s.nextInt();
                }

                s.nextLine();

                System.out.print("Do you wish to enter another? (y/n): ");
                choice1 = s.nextLine().toLowerCase().charAt(0); // read entire line
                if (choice1 != 'y') {
                    break;
                }

            }
        }
    }