Non-static variable cannot be referenced from a static context Explain

Question

class Program
{
    int count = 0;
    public static void main(String[] args)
    {
        System.out.println(count);
    }
}

But it gives the following error:

Main.java:6: error: non-static variable count cannot be referenced from a static context
        System.out.println(count);
                           ^

How can my class variables get recognized?

Answer 1

Static fields and methods are connected to the class itself and not its instances. If you have a class A, a 'normal' method b, and a static method c, and you make an instance an of your class A, the calls to A.c() and a.b() are valid. Method c() has no idea which instance is connected, so it cannot use non-static fields.

The solution for you is that you either make your fields static or your methods non-static. You main could look like this then:

class Program {
  public static void main(String[] args){
    Program programm = new Program();
    programm.start();
  }
  public void start(){
    // can now access non-static fields
  }
}

Answer 2

class Program
{
    int count = 0;
    public static void main(String[] args)
    {
         Program p=new Program();
         System.out.println(p.count);
    }
}