Java static block program

Java static block program

             class StaticBlock 

             {

  public static void main(String[] args) 

 {

    System.out.println("You are using Windows operating system.");

  }

  static 

  {

    String os = System.getenv("OS");

    if (os.equals("Windows_NT") != true) 

  {

      System.exit(1);

    }

  }

}