Static Initialization Blocks

Question

As far as I understood the \"static initialization block\" is used to set values of static field if it cannot be done in one line.

But I do not understand why we ne

Answer 1

static int B,H;
static boolean flag = true;
static{
    Scanner scan = new Scanner(System.in);
    B = scan.nextInt();
    scan.nextLine();
    H = scan.nextInt();

    if(B < 0 || H < 0){
        flag = false;
        System.out.println("java.lang.Exception: Breadth and height must be positive");
    } 
}