Java: How to get rid of checkstyle magic number warning?

Question

public class CharAt {

public static void main(String[] args) {

String name = "javatpoint";
int charPosition = 4; // <---- '4' is a magic number. How to fix?

char ch = name.charAt(charPosition);
System.out.println(ch);

}

}

Answer 1

@Nezuko

Thanks a lot! Just adding the 'final' keyword did the trick.

Answer 2

Aarti Agarwal but I thought that a good practise is to keep the scope of variables only where they are used. It's a variant of the rule "global variables are dangerous". I think his code doesn't have any mistakes

Answer 3

I executed your code in the code playground and it didn't give me any warning

Answer 4

Code playground doesn't work. I'm using Eclipse with the Checkstyle plugin @Rishi

Answer 5

I don't use Eclipse nor the plugin, but just wondering whether there is such an option to enable/disable that in the plugin's configuration? I just read its home page now, and it says the plugin can be configured easily.

Answer 6

I don't understand the error. For example, if I define a variable like,

int max_cards_in_a_deck=52;

The compiler saying 52 is a magic number is senseless. Or should I do like this?

#define FIFTY_TWO 52
int max_cards_in_a_deck=FIFTY_TWO;

XD

Answer 7

Aarti Agarwal exactly what I got. But this is different. He's not using a magic number in his code. He is defining a variable with a value and getting a warning

Answer 8

Aarti Agarwal I recommend you refer the link you posted😗

"A magic number is a direct usage of a number in the code."

To avoid this, one has to define the number with some named variable. Like,

Bad practise(using magic numbers):
createDeckOfCards(52);

Good practise(without magic numbers):
int cards_in_a_deck=52;
createDeckOfCards(cards_in_a_deck);

To avoid the use of magic numbers, @Solus has defined the number with a name, and this is producing a warning.

Right?

Answer 9

Aarti Agarwal I can't agree with you but okay =)