Null Pointer Exception - Basic Hangman Game!

Hi there,

I have been trying to make a simple console based Hangman game but I have come across a problem.

I am trying to make the game as Object Orientated as possible as this is what I have the most trouble with and I am trying to learn. The problem is that I am having three null pointer exceptions.

 public class GenerateWord {

	String words[] = new String[23];
	{words[1] = "dictionary";	words[2] = "restaurant";words[3] = "television";words[4] = "responsible";words[5] = "technology";
	words[6] = "collection";words[7] = "communicate";words[8] = "programming";words[9] = "federation";words[10] = "enterprise";
	words[11] = "exaggerate";words[12] = "cappuccino";words[13] = "monkey";words[14] = "computer";words[15] = "information";
	words[16] = "systems";words[17] = "poker";words[18] = "bottle";words[19] = "administration";words[20] = "encyclopedia";
	words[21] = "textbook";words[22] = "calculus";}
	
	String temp;
	public char [] generatedWord;
	public char [] hiddenWord;
	
	public char[] genWord(){
		Random getRandomWord = new Random();
		int n = getRandomWord.nextInt(22);
		temp = words[n];
		generatedWord = temp.toCharArray();
		return generatedWord;		
	}
	
	public char [] hidePhrase(){
		String temp = generatedWord.toString();
		String displayPhrase = temp.replaceAll(".", "*");
		char [] hiddenPhrase = displayPhrase.toCharArray();
		return hiddenPhrase;		
	}
}

import java.util.*;
public class CheckGuess{
	
   public void CheckGuess() {
	  
	   Guess guess = new Guess();
	   GenerateWord gen = new GenerateWord();
	   
	   char [] wordBin; //Still need to incorporate into program
	   char[] genWord = gen.generatedWord;
	   char[] hidWord = gen.hidePhrase();
	   
	   int guessWordLength = gen.generatedWord.length;
	   int maxGuesses = 20;
	   
	   while (maxGuesses > 0 || guessWordLength > 0){
		   char pGuess = guess.playerGuess();
		   for (int i = 0; i <genWord.length; i++){
			   if (genWord[i] == pGuess){
				   hidWord[i] = pGuess;
				   maxGuesses -= 1;
				   guessWordLength -= 1;
			   }
		   }
	   }	   
   }
}

public class HangmanTest {

	public static void main(String[] args) {
		GenerateWord test = new GenerateWord();
		Guess guess = new Guess();
		CheckGuess cGuess = new CheckGuess();
		test.genWord();
		test.hidePhrase();
		guess.playerGuess();
		cGuess.CheckGuess();

	}

}

Here are the three classes in problem, when I try and run the code this is the error which I am getting (the program runs but as soon as I enter a userinput this error occurs)


Exception in thread "main" java.lang.NullPointerException
at GenerateWord.hidePhrase(GenerateWord.java:29)
at CheckGuess.CheckGuess(CheckGuess.java:11)
at HangmanTest.main(HangmanTest.java:11)