Delayed Assignment

The declaration of a variable and the assignment of its initial value can be done separately.

public class Main {
    public static void main(String[] args) {
        String contestWinner;
        contestWinner = "Boaty McBoatface";

        System.out.println(contestWinner);
    }
}

In which case the "variable declaration" will only have the "type" and "name" components.

   String contestWinner;
//  type  name

And the "initial assignment" will look identical to a "re-assignment".

   contestWinner = "Boaty McBoatface";
//   name            initial value

Before an initial value is assigned to a variable, it is not allowed to be used.¹

public class Main {
    public static void main(String[] args) {
        String contestWinner;
        // This will not run, since Java knows that
        // you never gave contestWinner an initial value.
        System.out.println(contestWinner);
    }
}