string reverse in java

String str = "Hello";
String reverse(String str){
  StringBuilder sb = new StringBuilder();
  sb.append(str);
  sb.reverse();
  return sb.toString();
}// Java program to ReverseString using StringBuilder 
import java.lang.*; 
import java.io.*; 
import java.util.*; 
  
// Class of ReverseString 
class ReverseString 
{ 
    public static void main(String[] args) 
    { 
        String input = "Geeks for Geeks"; 
  
        StringBuilder input1 = new StringBuilder(); 
  
        // append a string into StringBuilder input1 
        input1.append(input); 
  
        // reverse StringBuilder input1 
        input1 = input1.reverse(); 
  
        // print reversed String 
        System.out.println(input1); 
    } 
} 
public class ReverseString {
    public static void main(String[] args) {
        String s1 = "neelendra";
        for(int i=s1.length()-1;i>=0;i--)
            {
                System.out.print(s1.charAt(i));
            }
    }
}