(Java) Program ignores Scanner at the point I want to enter a String

I have the following 3 Methods:

1. Method: Takes a text and splits its words in particular Strings and puts them into a String Array.

   
   
   

   public static String[] generateStringArray(String text) {
       if (text.isEmpty()) {
           throw new IllegalArgumentException(MSG_STRING_EMPTY);
   
       }
   
       // split pattern for all non word characters
       return text.trim().split("\\W+");
   }
   




2. Method: Counts the amount of Strings in an Array that consist solely out of Upper-Case or Lower-Case Letters.

   
   
   

   public static int countLowerUpperCaseStrings(String[] stringArray) {
       if (stringArray.length == 0) {
   
           throw new IllegalArgumentException(MSG_ARRAY_LENGTH_ZERO);
       }
   
       String convertedString;
       int counter = 0;
       char a;
       char b;
   
       for (int i = 0; i < stringArray.length; i++) {
           a = stringArray[i].charAt(0);
   
           b = stringArray[i].toLowerCase().charAt(0);
   
           if (a == b) {
               convertedString = stringArray[i].toLowerCase();
           } else {
               convertedString = stringArray[i].toUpperCase();
           }
   
           if (stringArray[i].compareTo(convertedString) == 0) {
               counter++;
   
           }
       }
       return counter;
   }
   




3. Method: The actual method, where you enter a text via Scanner and call for the other methods.

   
   
   

   public void numberOfUpperLowerCaseStrings() {
       String text;
       String[] stringArray;
   
   
       System.out.println("Enter a text:");
       text = input.nextLine();
       stringArray = Algorithmen.generateStringArray(text);
   
       System.out.println(Algorithmen.countLowerUpperCaseStrings(stringArray));
   }
   

Note that Algorithmen is the name of the class where the first two (static) methods are defined.

I tested the first two methods and they work just fine.

Now the problem comes into play, if I call the third method to firstly generate a text through the Scanner.

But somehow, the code just skips the line text = input.nextLine(); and throws the Exception (MSG) String is empty. The text "enter a text:" is executed, directly followed by the exception. But I am not able to enter any text.

if I change input.nextLine(); into input.next(), I am able to enter a text but after that, end up in an endless loop of exceptions.

So why can't I enter a text?

I have another two methods where input.nextLine works just fine.