How to reverse a string in Java with and without using StringBuffer.reverse() method?

1) Reverse string without using StringBuffer.reverse() method

Here, we will reverse the string without using StringBuffer.reverse() method, consider the given program:

import java.util.*;

class ReverseString
{
	public static void main(String args[])
	{
		//declaring string objects
		String str="",revStr="";
		
		Scanner in = new Scanner(System.in);
		
		//input string 
		System.out.print("Enter a string :");
		str= in.nextLine();
		
		//get length of the input string 
		int len= str.length();

		//code to reverse string 
		for ( int i = len- 1 ; i >= 0 ; i-- )
			revStr= revStr+ str.charAt(i);

		//print reversed string 
		System.out.println("Reverse String is: "+revStr);
	}
}

Output

Enter a string :Hello World!
Reverse String is: !dlroW olleH

2) Reverse string with using StringBuffer.reverse() method

Here, we will reverse the string using StringBuffer.reverse() method, consider the given program:

import java.util.*;

public class ReverseString 
{
	public static void main(String args[]) 
	{
		//declare string object and assign string
		StringBuffer str= new StringBuffer("Hello World!");
		
		//reverse the string
		str.reverse();
		
		//print the reversed string 
		System.out.println("String after reversing:" + str);
	}  
}

Output

String after reversing:!dlroW olleH