Different ways to reverse a String

This is a common question in many of the interview's, let it be a freshers interview or an experienced one!! Employers often look for a solution for building a program using recursion. So, this post has three ways to reverse a String and I hope it would be useful for beginners in Java.

Here goes the code :

package com.fcspoc.java;


public class StringReverse {
  
    public String reverseStringBuffer(String s) {
        return new StringBuffer(s).reverse().toString();
    }
  
    /* *
     * Reverse For Loop: Char Array
     */
    public String reverseCharArray(String s) {
        char[] reverseStringArray = new char[s.length()];
        for (int i = s.length() - 1, j = 0; i != -1; i--, j++) {
            reverseStringArray[j] = s.charAt(i);
        }
        return new String(reverseStringArray);
    }
  
    /**
     * Reverse For Loop: String Variable
     */
    public String reverseStringVariable(String s) {
        String reverseStringVariable = "";
        for (int i = s.length() - 1; i != -1; i--) {
            reverseStringVariable += s.charAt(i);
        }
        return reverseStringVariable;
    }
  
    public String reverseStringRecursion(String s) {
        if (s.length() <= 1) {
            return s;
        }
        return reverseStringRecursion(s.substring(1, s.length())) + s.charAt(0);
    }
  
    public static String reverseRecursionReverse(String str) {
        if ((null == str) || (str.length()  <= 1)) {
            return str;
        }
        return reverseRecursionReverse(str.substring(1)) + str.charAt(0);
    }
  
    public static void main(String[] args) {
        StringReverse stringReverse = new StringReverse();
        String s = "SAMPLETEST";
        String reverseStringBufferVar = stringReverse.reverseStringBuffer(s);
        System.out.println("Reverse String - String Buffer value is : "+reverseStringBufferVar);
        String reverseCharArrayVar = stringReverse.reverseCharArray(s);
        System.out.println("Reverse String - Char Array value is : "+reverseCharArrayVar);
        String reverseStringVariableVar = stringReverse.reverseStringVariable(s);
        System.out.println("Reverse String - String Variable value is : "+reverseStringVariableVar);
        String reverseStringRecursionVar = stringReverse.reverseStringRecursion(s);
        System.out.println("Reverse String - String Recursion Ex1 value is : "+reverseStringRecursionVar);
        String reverseRecursionReverseVar = reverseRecursionReverse(s);
        System.out.println("Reverse String - String Recursion Ex2 value is : "+reverseRecursionReverseVar);
    }
}