word counter on middle words in string

Question

So I have made a program that essentially finds and prints the middle names of a string entered by the user. I want the program to be able to print the middle names even if there are 4 names, for example; entering "joseph alan bloggs" would print "alan" but also entering "joseph alan steven bloggs" would print "alan steven"

So here is the bit i am stuck on I want it so that if the user enters 2 names or less an error message is printed telling the user to enter more names but currenty I am getting the following error.

Exception in thread "main" 
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
    at java.lang.String.substring(String.java:1937)
    at W4T2C.main(W4T2C.java:39)

My code is as follows

 Scanner sc = new Scanner(System.in);
        int count = 0;
        while (count < 2) 
        {
        System.out.print("Enter full name (at least 2 words): ");
        String name = sc.nextLine(); 
        // reads from the keyboard the name entered by the user

            String[] numNames = name.split(" ");
            // splits the string into different arrays by where the spaces are i.e. into the names
            for (int i = 0; i < numNames.length; i++) 
            {
                if (numNames[i].equals(" ")) 
                {
                } 
                else 
                {
                    count++;
                    System.out.println("Please enter 3 names or more");
                    // counts the number of names entered 


        int firstSpace = name.indexOf(" ");
        // finds the index of the first space in the name

        int lastSpace = name.lastIndexOf(" ");
        // finds the index of the last space in the name

        String middleName = "";
        // initially sets the middle name as nothing

               middleName = name.substring(firstSpace + 1, lastSpace);
               // sets the middle name as the set of string in between the index of the 
               // first space plus 1 and the last space i.e. the middle name/names

        System.out.println(middleName);
        // prints the middle name
        break;
    }

Thanks in advance guys...

Answer 1

Your error comes when the user enters single name and the first and last index becomes same.I don't think you need a loop for for count.Try this code:

public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        boolean flag = true;
        while (flag) {
            System.out.print("Enter full name (at least 2 words): ");
            // reads from the keyboard the name entered by the user
            String name = sc.nextLine();
            name = name.trim();
            if (!name.isEmpty()) {
                int firstSpace  = name.indexOf(" ");
                int lastSpace = name.lastIndexOf(" ");
                if (firstSpace != lastSpace) {
                    String middelName = name.substring(firstSpace + 1,
                            lastSpace);
                    System.out.println(middelName);
                    flag = false;
                } else {
                    System.out.println("Please enter 3 names or more");
                }

            }
        }
    }