What is a NumberFormatException and how can I fix it?

Question

Error Message:
Exception in thread \"main\" java.lang.NumberFormatException: For input string: \"Ace of Clubs\"
    at java.lang.NumberFormatException.forInputString         


        

Answer 1

A NumberFormatException is the way Java has to say you "I tried to convert a String to int and I could not do it".

In your exception trace you can read

Exception in thread "main" java.lang.NumberFormatException: For input string: "Ace of Clubs"
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:580)
    at java.lang.Integer.parseInt(Integer.java:615)
    at set07102.Cards.main(Cards.java:68)

Basically, it means that at the line 68 of your code you call to the Integer.parseInt method passing "Ace of Clubs" as paremeter. This method expects a integer value represented as String, e.g. "4", so method complains throwing a NumberFormatException because "Ace of Clubs" does not seem a integer at all.