从Java中的其他类访问变量

Question

Is there a way i can pass a variable from one class with main to another one with main method. For example

class A
{

    public static void main(String [] args)
    {

         int num = 5;
    }
}

class B
{
    public static void main(String []args)
    {
    }
}

Is there a way Class B can access int num from class A without getting null value?

Answer 1

num is a variable with scope only in the main() method. It effectively disappears once the method finishes up. This is true even considering that main() is static.

You can do this however:

class A {
    public int num = 5;
    public static void main(String[] args) {
    }
}

class B {
    public static void main(String[] args) {
        System.out.println(new A().num);     // should print '5'
    }
}

Notice that you need to create a new instance of A in order to access num , since num is an element of the object A .