Reversal of String in Java

public class StringReverse {

     public static void main(String[] args) {

           String str = "Paras";

           loopReverse(str);

           usingCollection(str);

           usingStringBuilder(str);

     }

     // using reverse() of StringBuilder

     static void usingStringBuilder(String str) {

          StringBuilder strReverse = new StringBuilder();

           strReverse.append(str);

           strReverse.reverse();

           System.out.println(strReverse);

     }

    

     // using charAt() of String class...

     static void loopReverse(String str) {

           String strReverse = "";

           int length = str.length();

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

                strReverse = strReverse + str.charAt(i - 1);

           }

           System.out.println(strReverse);

     }

    

     // Using reverse() of Collections Class...

     static void usingCollection(String str){

           List<Character> listChar= new LinkedList();

           char[] charString = str.toCharArray();

           for(char c:charString)

                listChar.add(c);

           Collections.reverse(listChar);

           Iterator itr=listChar.iterator();

           while(itr.hasNext())

                System.out.print(itr.next());

     System.out.println();

     }

}

Output:

saraP
saraP

saraP