// Read and save an integer, double, and String to your variables  
// write your code below this it is a simple and easy solution.


     String str = "is the best place to learn and practise coding!";
    a = scan.nextInt();
    b = scan.nextDouble();
    scan.nextLine(); // after reading double , it is used to avoid issue before reading a string
    str = scan.nextLine();

    System.out.println(i + a);
    System.out.println(d + b);
    System.out.println(s + str);        

"Complete the code in the editor below. The variables , , and are already declared and initialized for you. You must:"

In java 15 version there is no variables declared.

Solution in JavaScript :

// Declare second integer, double, and String variables. let secondInt; let secondDouble; let secondString

// Read and save an integer, double, and String to your variables.
secondInt = parseInt(readLine());
secondDouble = parseFloat(readLine());
secondString = readLine();

// Print the sum of both integer variables on a new line.
console.log(i + secondInt);

// Print the sum of the double variables on a new line.
console.log((d + secondDouble).toFixed(1));

// Concatenate and print the String variables on a new line
// The 's' variable above should be printed first.
console.log(s + secondString);

in java7`

            int a = scan.nextInt();``
      double b = scan.nextDouble();
      scan.nextLine();
      b+=d;
      String ss =scan.nextLine();
      System.out.println (i+a +"\n"+ b +"\n"+ s+ss );