Java static initializer block

 Hackerrank Java static initializer block By Java Tech Solutionz

Static initialization blocks are executed when the class is loaded, and you can initialize static variables in those blocks.

It's time to test your knowledge of Static initialization blocks. You can read about it here.

You are given a class Solution with a main method. Complete the given code so that it outputs the area of a parallelogram with breadth  and height . You should read the variables from the standard input.

If  or  , the output should be "java.lang.Exception: Breadth and height must be positive" without quotes.

Input Format

There are two lines of input. The first line contains : the breadth of the parallelogram. The next line contains : the height of the parallelogram.

Constraints

Output Format

If both values are greater than zero, then the main method must output the area of the parallelogram. Otherwise, print "java.lang.Exception: Breadth and height must be positive" without quotes.

Sample input 1

1
3

Sample output 1

3

Sample input 2

-1
2

Sample output 2

java.lang.Exception: Breadth and height must be positive

Solution:

static int B;
static int H;
static boolean flag = false;
static{
    Scanner scanner = new Scanner(System.in);
     B = scanner.nextInt();
     H = scanner.nextInt();
    
    if(B>0 && H>0){
        flag = true;
    }else{
        System.out.println( "java.lang.Exception: Breadth and height must be positive");
    }
}

Note:

Static Initialization Blocks
A static initialization block is a normal block of code enclosed in braces, { }, and preceded by the static keyword. Here is an example:
static {
    // whatever code is needed for initialization goes here
}
A class can have any number of static initialization blocks, and they can appear anywhere in the class body. The runtime system guarantees that static initialization blocks are called in the order that they appear in the source code.
There is an alternative to static blocks — you can write a private static method:
class Whatever {
    public static varType myVar = initializeClassVariable();
        
    private static varType initializeClassVariable() {

        // initialization code goes here
    }
}
The advantage of private static methods is that they can be reused later if you need to reinitialize the class variable