Null Pointer Exception

[Army]

I keep getting a Null Pointer Exception when I run my code. This is the bit that is highlighted.

/**Get the random word from the array*/
    public String getWords (){
        String randomWord = words[randy.nextInt(words.length)];
        return randomWord;
    }

private String[] words = {"apple", "beret", "arose", "along", "beamy", "becks", "decks", "barks",
                              "stark", "start", "stabs", "baggy", "asked", "asset", "asses", "audit",
                              "bowls", "boxes", "seats", "balls", "boats", "boxer", "brick", "bound",
                              "brass", "caked", "braid", "caged", "essay", "fault", "dents", "dutch",
                              "ethos", "dunks", "pains", "faxes", "mummy", "mixer", "mills", "might",
                              "moral", "teeth", "wings", "works", "walls", "tolls", "crawl", "toxin",
                              "bangs", "tough"};

[Wnt2bsleepin]

I don't see any highlighting, but it may be my eyes. I am assuming that the error is on line 3 in your first segment of code? Did you define the randy variable? Do you have access to the words array?

[Army]

What do you mean, access to the array? That might be my problem. How do you access an array? The bit that is highlighted is

String randomWord = words[randy.nextInt(words.length)];

[Wnt2bsleepin]

It is declared private. If it's not in the same class you won't be able to access it without a getter method. I ran the code you have above in a simple test class and it worked fine. It has to be something with your class organization.

[Army]

What would be a good "getter" method for it? Just like

public String getArray(){ return word; }

or something?

[Wnt2bsleepin]

That's fine. However, be careful with your return types.

[foulkelore]

Usually the getters and setter are the same name as the variables. Like this:

public String[] getWords() {
    return words;
}

public void setWords(String[] words) {
    this.words = words;
}

[PhQ]

You have most probably forgot to initialize the words array.

[Army]

Still throws a NullPointerException.

/**
 * TODO:
 * Make it print dashes for the letters.
 * Make it print the letter where index is.
 * Make it continue after start.
 * Add letter to the continue method.
 * Compare random word and selected indexes.
 * Find index of random word, use that index to put the letter into that index
 * then replace the '_' with the letter with that index.
 * Index with Element of the word
 * ...
 */



/** Import necessary packages*/
import java.util.Random;
import javax.swing.JOptionPane;
import java.util.Scanner;
import java.lang.String;

public class Hangman extends BasicGame
{
    /**Call all of the variables*/
    Random randy = new Random();
    private int guesses;
    private final int maxGuesses = 6;
    private String myGeneratedRandomWord = getWords();
    private String letter;
    private String randomWord = "";
    private String itsGuessedLetter = "";
    private String itsSolvedWord = "-----";
    private String[] words = {"apple", "beret", "arose", "along", "beamy", "becks", "decks", "barks",
                              "stark", "start", "stabs", "baggy", "asked", "asset", "asses", "audit",
                              "bowls", "boxes", "seats", "balls", "boats", "boxer", "brick", "bound",
                              "brass", "caked", "braid", "caged", "essay", "fault", "dents", "dutch",
                              "ethos", "dunks", "pains", "faxes", "mummy", "mixer", "mills", "might",
                              "moral", "teeth", "wings", "works", "walls", "tolls", "crawl", "toxin",
                              "bangs", "tough"};
    public String[] getWord(){
        return words;
    }
    
    /**Get the random word from the array*/
    public String getWords (){
        String randomWord = getWord()[randy.nextInt(getWord().length)];
        return randomWord;
    }
    
    /**Get the indexes of the letter of the random word indices don't start with 1*/
    public String getSelected(){
        return itsGuessedLetter;
    }
    
    /**Finds index of the letter of randomWord*/
    public int getIndex(){
        int index = getWords().indexOf(getSelected());
        return index;
    }
    
    /**Get the first input, set strikes to zero, get the random word*/
    public void start(){
        guesses = 0;
        getWords();
        JOptionPane.showMessageDialog(null, "Your word is: " +itsSolvedWord);
        itsGuessedLetter = JOptionPane.showInputDialog(null, "Make your guess!");
        int index = myGeneratedRandomWord.indexOf(itsGuessedLetter);
        if(myGeneratedRandomWord.indexOf(itsGuessedLetter ) != -1) {
            // it contains the letter
            if(index >= 0){
                itsSolvedWord = itsSolvedWord.substring(0,index)+itsGuessedLetter+itsSolvedWord.substring(index + 1);
                JOptionPane.showMessageDialog(null, "Updated word: " +itsSolvedWord);
            }
       }
       else {
            // wrong guess
            guesses++;
       }
    }
    
    /**Continue the game on, checks if the letter is there if not then apply the letter*/
    public void continueGame(){
       itsGuessedLetter = JOptionPane.showInputDialog(null, "Make another guess!");
       int index = myGeneratedRandomWord.indexOf(itsGuessedLetter);
       if(myGeneratedRandomWord.indexOf(itsGuessedLetter ) != -1) {
            // it contains the letter
             itsSolvedWord = itsSolvedWord.substring(0,index)+itsGuessedLetter+itsSolvedWord.substring(index + 1);
       }
       else {
            // wrong guess
            guesses++;
       }
    }
    
    /** Runner basically*/
    public void mainScreen (){
        start();
        while (guesses != maxGuesses){
            continueGame();
            checkBodyParts();
        }
        gameOver();
    }
    
    /**Gets the */
    
    
    /**After certain strikes head is called etc.*/
    public void checkBodyParts(){
        if(guesses == 1){
            JOptionPane.showMessageDialog(null, "You now have a head! Wrong guesses left: 5");
        }
        if(guesses == 2){
            JOptionPane.showMessageDialog(null, "You now have a body! Wrong guesses left: 4");
        }
        if(guesses == 3){
            JOptionPane.showMessageDialog(null, "You now have a right arm! Wrong guesses left: 3");
        }
        if(guesses == 4){
            JOptionPane.showMessageDialog(null, "You now have a left arm! Wrong guesses left: 2");
        }
        if(guesses == 5){
            JOptionPane.showMessageDialog(null, "You now have a right leg! Wrong guesses left: 1");
        }
        if(guesses == maxGuesses){
            JOptionPane.showMessageDialog(null, "You lose!");
        }
    }
    
    /**You lose.*/
    public void gameOver(){
        JOptionPane.showMessageDialog(null, "Game Over!");
        System.exit(0);
    }
}

[PhQ]

Can you provide the whole error?

[Army]

java.lang.NullPointerException
	at Hangman.getWords(Hangman.java:46)
	at Hangman.<init>(Hangman.java:28)
	at GameApp.main(GameApp.java:9)

[Wnt2bsleepin]

You don't need the

public String[] getWord(){
        return words;
    }

because the words array is visible to the class. You don't need a getter. You need to debug a bit. Try separating line 46 into different segments.

[PhQ]

You get this error because your variable words is null. Like I said above, you need to initialize the variable.

[Army]

How do I initialize it??? Everything I go through it says it's initialized.

[Wnt2bsleepin]

Follow the code from the top to the bottom and see if you can find the error.

[PhQ]

How do I initialize it??? Everything I go through it says it's initialized.

Read through this: Lesson: Language Basics (The Java™ Tutorials > Learning the Java Language)

[Army]

Really, if you know where it is just tell me. I've had this problem for two weeks now and I'm pretty tiered of it.

[Army]

Read through this: Lesson: Language Basics (The Java™ Tutorials > Learning the Java Language)

Alternatively, you can use the shortcut syntax to create and initialize an array:

int[] anArray = {
100, 200, 300,
400, 500, 600,
700, 800, 900, 1000
};

Tells me nothing.

[Wnt2bsleepin]

Look at the order you are trying to access the array at

private String myGeneratedRandomWord = getWords();

See anything wrong with that being there?

[Army]

Look at the order you are trying to access the array at

private String myGeneratedRandomWord = getWords();

See anything wrong with that being there?

Ah, ok, thanks. It works now XD