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Thread: Word Guess program with a Null Pointer Exception

  1. #1
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    Question Word Guess program with a Null Pointer Exception

    Hello,

    I keep receiving the Null Pointer Exception error in my code and I am not sure how to fix it. The program I am working on is a Word Guess program that is kind of like jeopardy. I am coding this in Eclipse, by the way.

    public class WordGuess 
    {
    	//global variables
    	static Scanner myScanner;
    	static Scanner datScanner;
    	static File inFile;
    	static String[] words = new String[10];
    	static String guessWord;
    	static String dashWord;
    	static String numCtr;
    	static String guess;
     
         public static void input()
    	{
    		int i = 0;
    		int guessCtr = 15;
    		dashWord = guessWord;
    		dashWord.replaceAll("[A-Z]", "-"); //this is where I get the error
     
    		System.out.println("Guesses left: " + guessCtr + "    " + dashWord);
     
    		System.out.print("Enter letter: ");
    		guess = myScanner.next();
     
    		guessValid();
     
     
    			for(i = 0; i < guessWord.length() && guessCtr > 0; i++)
    			{
    				if(guessValid())
    				{
    					if(guessWord.substring(i, i + 1).equals(guess))
    					{
    						guess.replace(dashWord.substring(i, i + 1), guess);
    					}
    					else
    					{
    						guessCtr--;
    					}
     
    					System.out.println("Guesses left: " + guessCtr + "    " + guessWord);
     
    					System.out.print("Enter letter: ");
    					guess = myScanner.next();
     
    				}
    			}
     
    			System.out.println("Sorry, you fail!");
    	}


  2. #2
    Member Zyrion's Avatar
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    Default Re: Word Guess program with a Null Pointer Exception

    Usually when your compiler receives a NullPointerException, it is when you are trying to use a object that points to a null value.

  3. #3
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    Default Re: Word Guess program with a Null Pointer Exception

    Yes, I know that it points to a null value, but I cannot figure out why dashWord would have a null value.

  4. #4
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    Default Re: Word Guess program with a Null Pointer Exception

    your guessWord is get a null value..Because you only declare the guessword like this static String guessWord; after that you didn't assign values on that.. and also directly you pass the guessword into dashword like this
    dashWord = guessWord; with out assigning

    i think this is the reason the null pointer exception is come on runtime...

    So you try to assign some value to guessword after that you pass the values into another variable like this..
    guessWord="Hi";
    dashWord = guessWord;
    Regards
    Android developer
    Trinay Technology Solutions
    http://www.trinaytech.com
    5705750475

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