Global Fields

You can make field declarations outside of a class. This makes these fields "global" to the program.

We call things global when they are available at every point in the "world" of our program.1

int number = 0;

void main() {
    System.out.println(number);
    number++;
    System.out.println(number);
}
1

This explanation is I think a correct description of what it means to be global, but what I am showing won't really hold up as a global thing the more you learn.