Reverse a String java code example

Example 1: reverse string java

// Use StringBuilder for non-thread environment, it is faster
String string="whatever";
String reverse = new StringBuilder(string).reverse().toString();
System.out.println(reverse);

Example 2: Reverse a string in java without using reverse function

// Reverse a string in java without using reverse function
import java.util.Scanner;
public class ReverseWithoutFunction 
{
   public static void main(String[] args) 
   {
      Scanner sc = new Scanner(System.in);
      System.out.println("Please enter a string: ");
      String strInput = sc.nextLine();
      int len = strInput.length();
      String strReverse = "";
      System.out.println("Reverse a string without using reverse function: ");
      for(int a = len - 1; a >= 0; a--)
      {
         strReverse = strReverse + strInput.charAt(a);
      }
      System.out.println(strReverse);
      sc.close();
   }
}

Example 3: java reverse a string

// Library approach
public static String solution(String str) {
	// StringBuilder is not thread-safe, use StringBuffer
	return new StringBuffer(str).reverse().toString();
}

// DIY approach
public static String solution(String str) {
	char[] chars = str.toCharArray();
	for(int i = 0, j = str.length() - 1; i < j; i++, j--) {
		char ch = chars[i];
		chars[i] = chars[j];
		chars[j] = ch;
	}
	return new String(chars);
}

Example 4: how to reverse a string in java

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));
            }
    }
}

Example 5: reverse string java

String string="whatever";
String reverse = new StringBuffer(string).reverse().toString();
System.out.println(reverse);

Example 6: java string reverse

String str = "Reverse this strings";
//for loop
for (int i = str.length() - 1; i >= 0; i--) {
	System.out.print(str.charAt(i));
}

// StringBuffer for multi thread
StringBuffer sb = new StringBuffer(); 
sb.append(str);
System.out.print(sb.reverse().toString());

// StringBuffer for single thread
StringBuilder sb = new StringBuilder(); 
sb.append(str);
System.out.print(sb.reverse().toString());