Creating global variables - Java

Question

I am getting a compiling error for this code:

public class Matching {        
    public static int match = (int) Math.floor(Math.random()*cities.size()); //Error is here
}

I'm want to make "match" a global variable.

My compiling error is:

"Illegal static declaration in inner class testingProgram.Matching modifier 'static' is only allowed in constant variable declarations

Usage of static non-final variable during initialization."

Don't know what the error means, nor do I know how to fix it.

If you don't plan to change the variable, add the final keyword before or after static. — Jacob G.
– Jacob G., Commented Jun 10, 2017 at 12:34
What is cities variable? Your code is not clear, and it is not possible to test it. — Mostafa Barmshory
– Mostafa Barmshory, Commented Jun 10, 2017 at 12:38

Sergey Kalinichenko · Accepted Answer · 2017-06-10 12:34:13Z

2

This happens because your Matching class is located inside another class called testingProgram, and is not static.

Java allows static fields inside an inner class only when the inner class itself is static. You can fix this problem in several ways:

By making Matching a static inner class,
By making Matching a top-level class, or
By making static int match final, i.e. final static int match

answered Jun 10, 2017 at 12:34

Sergey Kalinichenko

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1 Comment

Mostafa Barmshory Over a year ago

How do you know it is an inner class?

Chris Sharp · Accepted Answer · 2017-06-10 12:36:40Z

0

Create the variable in some static class (main, for example) and make sure it gets passed to the constructor of this class. I don't know why you are doing this but the reason it's difficult is because it's not a good idea. If you need to save the state of 'match' then give more information.

public static void main() {
    int match;
    Matching m = new Matching(match);
}

answered Jun 10, 2017 at 12:36

Chris Sharp

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