content: import java.util.Scanner;
  
  class Hello {
      public static void main(String[] args) {
          System.out.println("Hello World!");
  
          System.out.println();
  
          System.out.println(3 + 2);
          System.out.println(3 - 2);
          System.out.println(3 * 2);
          System.out.println(3 / 2);
  
          // double
          System.out.println(3.0 / 2);
  
          System.out.println();
  
          // http://wtf.org/
          System.out.println(((Object)3.0).getClass());
          System.out.println(((Object)3.0f).getClass());
          System.out.println(Double.class.isInstance(3.0));
          System.out.println(Float.class.isInstance(3.0f));
  
          System.out.println();
  
          int a = 3;
          int b = 2;
  
          System.out.println(a);
          System.out.println(b);
          System.out.println(a + ", " + b);
  
          System.out.println();
  
          // Wrong!
          System.out.println(a + " + " + b + " = " + a + b);
  
          // Fix
          System.out.println(a + " + " + b + " = " + (a + b));
  
          System.out.println();
  
          System.out.println("-".repeat(80));
  
          // Input
  
          System.out.print("What's your name? ");
  
          Scanner scanner = new Scanner(System.in);
          String name = scanner.nextLine();
          scanner.close();
  
          System.out.println("Hello, " + name + "!");
      }
  }
  