Java NullPointerException in Array

Question

I get an error when I do the following operation.

public static String text = "ng"; 
public static String[] specialConsonants = new String[4];
public static String[] specialConsonantsUni = new String[6];

public void setSpecial(){
    specialConsonantsUni[0] = "ං";
    specialConsonants[0] = "ng";
    specialConsonantsUni[1] = "ඃ";
    specialConsonants[1] = "h/g";
    specialConsonantsUni[2] = "ඞ";
    specialConsonants[2] = "N/g";
    specialConsonantsUni[3] = "ඍ";
    specialConsonants[3] = "R/g";
    // special characher Repaya
    specialConsonantsUni[4] = "ර්" + "\u200D";
    specialConsonants[4] = "/R/g";
    specialConsonantsUni[5] = "ර්" + "\u200D";
    specialConsonants[5] = "/\\r/g";
}
public static void main(String args[]){

    for (int i=0; i < specialConsonants.length; i++){
        text = text.replace(specialConsonants[i], specialConsonantsUni[i]);
        System.out.println(text);
    }
}

I'm trying to create a locale app. So you may not see some fonts. The error is following.

Exception in thread "main" java.lang.NullPointerException
at java.lang.String.replace(Unknown Source)
at in.isuru.srtuc.Stuff.main(Stuff.java:223)

it appears that you must call your setSpecial() method to initialize the values of the array — Luiggi Mendoza
– Luiggi Mendoza, Commented Feb 26, 2012 at 15:57

om-nom-nom · Accepted Answer · 2012-02-26 15:57:32Z

1

specialConsonants and specialConsonantsUni are not initilized. You've just defined setSpecial() but not called it before doing replaces

The correct behavior would be:

public static void main(String args[]){
    setSpecial();
    for (int i=0; i < specialConsonants.length; i++){
        text = text.replace(specialConsonants[i], specialConsonantsUni[i]);
        System.out.println(text);
    }
}

note also that setSpecial should be static in that case

Moreover you have to change dimension of specialConsonants to 6

answered Feb 26, 2012 at 15:57

om-nom-nom

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Comments

Noel M · Accepted Answer · 2012-02-26 15:59:51Z

1

Because specialConsonants[i] is null. You have not initialized it.

its like

specialConsonants = {null,null,null,null}

You need to make function setSpecial static then call it before the loop.

edited Feb 26, 2012 at 15:59

Noel M

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answered Feb 26, 2012 at 15:57

JProgrammer

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Comments

Mahesh · Accepted Answer · 2012-02-26 15:56:44Z

0

public static String[] specialConsonants = new String[4];

public void setSpecial(){
    // ...
    specialConsonants[5] = "/\\r/g";
}

specialConsonants is of array size 4. There is no 5th index for it. Also you haven't called the array initializer method.

answered Feb 26, 2012 at 15:56

Mahesh

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Comments

ApprenticeHacker · Accepted Answer · 2012-02-26 15:58:06Z

0

You're adding elements to an already filled array. Array indexes start from 0, When you declared :

 public static String[] specialConsonants = new String[4];

That means you can only use specialConsonants[0] to specialConsonants[3]

I suggest you use a hashmap for this thing.

HashMap<String, String> specialConsonants = new HashMap<String, String>();
....
specialConsonants.put("ං" , "ng" );
....

answered Feb 26, 2012 at 15:58

ApprenticeHacker

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Comments

Adam Liss · Accepted Answer · 2012-02-26 15:59:02Z

0

You've declared specialConsonants as an array of length 4, but you're assigning 6 elements to it.

specialConsonants[4] has enough room for elements 0, 1, 2, and 3. You need to declare it as specialConsonants[6] if you want indices 0 - 5.

Then you need to call setSpecial() before you use the array in your loop.

answered Feb 26, 2012 at 15:59

Adam Liss

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Comments

Simon Wang · Accepted Answer · 2012-02-26 15:59:52Z

0

the array definition looks wrong, seems you want two same size array but you defined as :

public static String[] specialConsonants = new String[4];
public static String[] specialConsonantsUni = new String[6];

I think it should be:

public static String[] specialConsonants = new String[6];
public static String[] specialConsonantsUni = new String[6];

answered Feb 26, 2012 at 15:59

Simon Wang

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