创建全局变量-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.

Answer 1

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, ie final static int match

Answer 2

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);
}