NullPointerException error

Hi, my program reads out of a textfile containing about 20 hockey players. At the beginning of the program, the user is given the option to sort by name, rating, club or position. No matter what I press, I always get a nullpointerexception error. This never happened before and the program works fine on my friends computer, it also used to work fine on mine and then I randomly got this error. What do I do to fix this?


This is what is says in the bluej thingy



java.lang.NullPointerException
at java.lang.String$CaseInsensitiveComparator.compare (String.java:1217)
at java.lang.String$CaseInsensitiveComparator.compare (String.java:1211)
at java.lang.String.compareToIgnoreCase(String.java:1 258)
at FINAL.sort(FINAL.java:206)
at FINAL.options(FINAL.java:48)
at FINAL.main(FINAL.java:41)

Quote:

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What do I do to fix this?

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Your first need to post code, preferably an abbreviated version, which clearly demonstrates the problem. The stack trace you posted provides a lot of information but is meaningless without the context of the code that throws the exception.

I get the error at this part of my program. It's weird though, it was working on my computer a few days ago and I suddenly got this error.

Code Java:

---

  if(options.equalsIgnoreCase("A"))
        {
            for (int x=0; x<players.length; ++x)
            {
                for (int y=0;y<players.length-1; ++y)
                {
                    if (players [y][0].compareToIgnoreCase(players [y+1][0]) > 0)  
                    {  
                        for(int b=0;b<=4;b++)
                        {
                            String temp = players [y][b];          
                            players [y][b] = players [y + 1][b];      
                            players [y + 1][b] = temp;
                        } 
                    }
                }
            }
        }

---

Better, but the code still doesn't provide much context. An SSCCE is much more demonstrative. As is, I could guess that not all of your players array has been instantiated.

Thanks, it works now. i have another question, when I add a player to the database, it works fine. But when I try to remove a player from the database, it doesn't work. Another thing is, after I use the remove function, the other functions won't work anymore (for example, after using remove, i tried to sort the players by name, it didn't work because I got an array out of bounds error) Here is the code I use for adding players

Code Java:

---

public static void add(String players [][],String args[]) throws IOException
    {   
        BufferedReader c = new BufferedReader(new InputStreamReader(System.in));
 
        PrintWriter output = new PrintWriter ( new FileWriter ("nhlstats.txt",true));//append file
 
        System.out.println ("Enter the name of the player (first then last)");
        String hplayer = c.readLine ();
 
        System.out.println ("Enter the position(C,RW,LW,D,G) of " + hplayer);
        String posadd = c.readLine ();
 
        System.out.println ("Enter the rating of " +hplayer);
        String ratingadd=c.readLine ();
 
        System.out.println ("Enter the country of origin of " + hplayer);
        String countadd = c.readLine ();
 
        System.out.println ("Enter the current team " + hplayer + " plays for");
        String clubadd = c.readLine ();
 
        System.out.println ("");
        System.out.println ("");
        System.out.println("The player has been added toe.");
        System.out.println("Please see text file for the added players.");
 
        int x = 0;    
        for (int i = 0 ; i <=players[x].length-1 ; ++i)
        {
            if (players [x][0] == null)
            {
                i = x;
                break;
            }
        }
        players [x][0] = hplayer;
        players [x][1] = posadd;
        players [x][2] = ratingadd;
        players [x][3] = countadd;
        players [x][4] = clubadd;
        output.println ();
        output.println (hplayer);
        output.println (posadd);
        output.println (ratingadd);
        output.println (countadd);
        output.println (clubadd);
        output.close();
        for (int j=0; j<players.length; ++j)//sort the name after it is added
            {
                for (int y=0;y<players.length-1; ++y)
                {
                    if (players [y][0].compareToIgnoreCase(players [y+1][0]) > 0)  
                    {  
                        for(int b=0;b<=4;b++)
                        {
                            String temp = players [y][b];          
                            players [y][b] = players [y + 1][b];      
                            players [y + 1][b] = temp;
                        } 
                    }
                }
            }
    }

---

The code I "tried" to use for removing players from the database is:

Code Java:

---

public static void takeout(String players[][],String args[]) throws IOException
    {
        BufferedReader c = new BufferedReader (new InputStreamReader (System.in));
        PrintWriter out = new PrintWriter ( new FileWriter ("nhlstats.txt"));
        System.out.println ("What do you want to remove?.");
        String read = c.readLine ();
        for (int x =0; x<=players.length-1; ++x)
        {   
 
            if (players[x][0] != null)     
            {
 
                if (players[x][0].equalsIgnoreCase(read))     
                {
                    for (int y = 0; y <= 4; ++y)
                    {
                        players [x][y] = null;
                    }
                }
 
 
            }
        }
 
        for (int x =0; x<=players.length-1; ++x)
        {   
            for (int y = 0; y <= 4; ++y)
            {
                if (players[x][y] != null)
                {
                    out.println(players[x][y]);
                }
            }
            out.close();
        }
    }

---

I think what happens is that instead of that specific player getting deleted from the text file, all the players get deleted. How do I delete only one player?

I really don't mean to be rude, but can someone please help me?

please help!

Please don't bump threads. I recommend you read the Welcome Announcements, in particular clause F. Moreover, you've provided very little information for us to help. "It doesn't work" could mean a million things. Describe the behavior you expect, and the behavior you receive (suggested reading: How To Ask Questions)