字符串数组中的 NullPointerException

Question

When ever I run this method to give out the required data about a customer - it's a flight club program - it returns nothing as if nothing has ever been entered.

NullPointerException most be the issue, because also when I run another method (will follow, too) to give some data, NullPointerException appears, however only when there has been no data entered:

First method which gives data about the user:

public static void ausgabeBuchung(String[] name, String[] surname, int[] time, int[] flightNumber, String[] description, String[] reservation) {
    System.out.println("Alle ihrer Buchungen");
    for (int i = 0; i < name.length-1; i++) {
        System.out.println("the flight number: " + flightNumber[i]);
        System.out.println("the description: " + description[i]);
        System.out.println("time of the reservation: " + time[i]);
        System.out.println("name of the person: " + name[i]);
        System.out.println("Surname of the person: " + surname[i]);
        System.out.println("Reservation type: " + reservation[i] + "\n");
    }
}

Second Method which checks if any flights are available:

public static void verfügbar( String[] name, String[] description, int[] time, String[] reservation) {
    for (int i = 0; i < description.length; i++) {
        if (vorname[i] == " ") {
            System.out.println("The flight with the description: " + description[i] + " is free the whole day");
        } else if (buchung[i].equals("Ganze Tag")) {
            System.out.println("The flight with the description: " + description[i] + " is reserved the whole day");
        }
        else{
            System.out.println("The Flight with the description " + description[i] + " ist from: " + time[i]++ + " till: " + time[i] + " reserved");
        }
    }
}

Answer 1

It looks like you are using the index of a set of arrays as a sort of suedo-Object. The problem you are probably running into in the first method is the name array has a different number of values in it than the other arrays. If each index of these arrays are all related to only each other then why not just create a Reservation object?

Public class Reservation {
   String Name;
   String surname;
   int time;
   int flightNumber;
   String description;
   String reservation;
}

And then create just a single array of Reservations.

This will make it much easier to iterate through without worrying about keeping the array sizes the same.

Answer 2

Check if any of these Arrays is not null before use, maybe when you calling the method to send some null array

You should check if any argument is null

public static void ausgabeBuchung(String[] name, String[] surname, int[] time, int[] flightNumber, String[] description, String[] reservation) {
    if ( name == null || surename == null || time == null || flightNumber == null || description == null || reservation == null ) {
      throw new IllegalArgumentException("Please enter valid arrays");
    }
}

Answer 3

i < name.length-1

is your issue, as your loop will always omit the last name.