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

int first_value = Integer.parseInt(cards[index]); 

while writing the above statement, you are trying to parse "Ace of Clubs" as a number.

you can use the following method to test if any string can be parsed as Integer:

boolean tryParseInt(String value) {  
     try {  
         Integer.parseInt(value);  
         return true;  
      } catch (NumberFormatException e) {  
         return false;  
      }  
}

Regarding your question, what is NumberFormatException : It is thrown to indicate that the application has attempted to convert a string to one of the numeric types, but that the string does not have the appropriate format. (ref -http://docs.oracle.com/javase/7/docs/api/java/lang/NumberFormatException.html)