Write a Java Program Without using reverse function?

Write a Java Program Without using reverse Funtion?

import java.util.Scanner;

public class ReverseStringWithoutReverseFunction {

       public static String reverse(String str) {

              StringBuilder sb = new StringBuilder();

              char[] string = str.toCharArray();

              for (int i = string.length - 1; i >= 0; i--) {

                     sb.append(string[i]);

              }

              System.out.println(sb.toString());

              return sb.toString();

       }

       public static void main(String[] args) {

              Scanner keyboard = new Scanner(System.in);

              System.out.println("Enter a String:");

              String input = keyboard.next();

              reverse(input);

       }

}